انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2026 01 21 The contract of providing necessaries for the ship and its conflict with maritime mortgage (Comparative study in American, English, and Iranian law) قرارداد تأمین مایحتاج برای کشتی و تزاحم آن با رهن دریایی (مطالعه تطبیقی در حقوق آمریکا، انگلیس و ایران) 1 15 209644 10.22113/jmst.2024.481943.2613 FA آرزو پادیر گروه حقوق خصوصی، دانشکده حقوق و علوم سیاسی، دانشگاه شیراز، شیراز، ایران 0009-0004-8912-0427 علی رضائی گروه حقوق خصوصی، دانشکده حقوق و علوم سیاسی، دانشگاه شیراز، شیراز، ایران 0000-0003-0423-5299 Journal Article 2024 10 10 ABSTRACT The maritime mortgage is considered a contractual pledge that creates the objective right of the mortgagor on the maritime property to guarantee the payment of his claimant. Considering the strong economic and commercial effects and importance of supplying ships' necessaries on marine transport, the main question of this research is what is the position of maritime law for the supplier of necessaries in line with his claimant and the ranking of his right in conflict with the naval mortgagor's right Does it take into account? In response, by applying the descriptive-analytical method and using library resources, it was concluded that in American law, while amending and updating laws according to commercial needs and requirements, in some cases explicitly or implicitly, the demand of the supplier The needs of the ship have prevailed over the demands of the mortgagor. Also, common law and general legal principles have established conditions and rules regarding transactions related to the provision of ship's necessaries to protect other creditors, including the mortgagor. Violation of any of these conditions and regulations can lead to the loss of priority and superiority to the extent of other maritime claimants without contractual and judicial guarantees. Therefore, foreign naval law does not face any challenge in terms of the existence of binding rules regarding the conflict and encroachment of the right of the mortgagor and the supplier of necessaries, but regarding Iranian law, the law needs to be reformed and updated, and proposals have been made in this regard. INTRODUCTION Since Iran has about 2700 km of water border and on the other hand, due to the bulk transportation of commercial cargoes through ships in the sea, the issues related to maritime transportation, including the conflict of rights of maritime creditors, are of great importance. No independent work has been written in Iran regarding the conflict between the rights of suppliers of ship's necessaries and other creditors, including maritime mortgagors; Therefore, in this article, an attempt has been made to define the ship's necessaries, to explain the rights of the supplier of the ship's necessaries and its rulings, as well as to explain how to resolve the conflict between these rights and the maritime mortgagor's right. MATERIALS AND METHODS The following article, with the descriptive-analytical method and using library resources and legal documents, seeks to investigate the solutions to conflict and conflicts arising from the provision of ship's necessaries and maritime mortgagor, with an emphasis on the laws of Iran, England, and America. In England, in addition to the judicial procedure, the English Merchant Shipping Act of 1995, which came into force on January 1, 1996, with subsequent amendments, and in the United States, the Commercial Instrument and Maritime Liens Act (CIMLA), which replaced the Ship Lien Act of 1920 in 1989, apply to mortgage and Maritime lien prevails. In our country, the maritime law of 1343 is also valid in this field. Therefore, this article is formatted in two main topics: "Description of provision of ship's necessaries, its conditions and provisions" and "Conflict between the right of the supplier of necessaries and the maritime mortgagor". RESULTS this first part will describe the provision of the ship's necessaries, its conditions and provisions, and then the conflict between the rights of the supplier of the ship's necessaries and the maritime mortgagor will be evaluated and analyzed based on the principles and rules of Iranian, English, and American law. DISCUSSION AND CONCLUSION In order to solve the defects, it is suggested that the legislator, by using the legislative experience and judicial procedure of advanced countries, maintain the maritime lien on the ship for the providers of necessaries, forming a maritime court, and facilitate the enforcement and enforcement of the rights of maritime creditors, should rush to support the aforementioned. Paying attention to the legal personality of the ship can play a constructive and important role in this development. رهن دریایی یک وثیقه قراردادی محسوب می شود که موجب ایجاد حق عینی مرتهن بر روی مال دریایی جهت تضمین پرداخت طلب او می شود. مرتهن می تواند در صورت تخلف راهن در اجرای تعهداتش، با برخورداری از حق تعقیب و تقدم، مال دریایی را توقیف و به فروش برساند و از وجه حاصل طلب خود را وصول نماید. با توجه به اثرات و اهمیت شدید اقتصادی و تجاری تأمین ملزومات کشتی بر حمل و نقل دریایی، سوال اصلی این پژوهش آن است که حقوق دریایی چه جایگاهی برای تأمین کننده ملزومات در راستای استیفاء طلب خود و رتبه بندی حق وی در تزاحم با حق مرتهن دریایی در نظر می گیرد؟ در پاسخ، با به کارگیری روش توصیفی – تحلیلی و بهره گیری از منابع کتابخانه ای این نتیجه حاصل آمد که در حقوق آمریکا ضمن اصلاح و به روزرسانی قوانین با توجه به نیازها و مقتضیات تجاری در برخی موارد به صورت صریح یا ضمنی، طلب تأمین کننده مایحتاج کشتی بر طلب مرتهن برتری یافته است. همچنین حقوق عرفی و اصول کلی حقوقی نیز شرایط و قواعدی را در خصوص معاملات مربوط به تأمین مایحتاج کشتی در جهت حمایت از سایر طلبکاران از جمله مرتهن مقرر نموده است. نقض هر یک از این شرایط و قواعد می‌تواند منجر به از دست دادن اولویت و برتری تا حد سایر طالبکاران دریایی بدون وثیقه قراردادی و حکمی شود. بنابراین حقوق دریایی خارجی از نظر وجود قواعد الزام‌آور در رابطه با تزاحم و تعرض حق مرتهن و تأمین‌کننده ملزومات با چالش مواجه نیست، امّا در خصوص حقوق ایران، قانون نیازمند اصلاحات و به روزرسانی است که پیشنهاداتی در همین راستا ارائه گردیده است.

https://jmst.kmsu.ac.ir/article_209644_d571f7c2b185f0b103226f5f71694e68.pdf

انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2026 01 21 An attempt to determine and evaluate the economic factors affecting maritime transport in the Caspian Sea: Container and Bulk Shipping تعیین و ارزیابی تاثیر شاخص‌های اقتصادی بر حمل‌و‌نقل دریایی دریای خزر: حوزه انتقال فله و کانتینری 16 29 209647 10.22113/jmst.2024.483140.2615 FA سعید فرهادی پور گروه مدیریت بازرگانی، دانشکده مدیریت و اقتصاد، دانشگاه آزاد اسلامی واحد علوم و تحقیقات، تهران، ایران غزال اسدالهی گروه مدیریت بازرگانی، دانشکده مدیریت و اقتصاد، دانشگاه آزاد اسلامی واحد علوم و تحقیقات، تهران، ایران 0000-0003-1427-7273 Journal Article 2024 10 20 ABSTRACT The Caspian Sea's significance and strategic location in the Middle East, Central Asia, Europe, and the Caucasus for trade and transport necessitate fostering regional and international economic and political relationships. Political and economic factors influence the formation of security and economic cooperation development strategies. To enhance Iran's portion of resources and benefits from the Caspian Sea, we analyzed economic factors from 2014 to 2024 and assessed how they affect maritime transportation in the region. Data was gathered from the databases of the United Nations, the World Bank, and the Ports and Maritime Organization of Iran. We applied a regression model to assess the influence of certain parameters. The results of this study show that the population changes in countries will impact the amount of sea transportation and the demand for trade to fulfill a country's basic needs through importing and exporting. Utilizing findings to implement effective measures and plans for sea transportation, based on analyzing economic indicators, can greatly enhance goal-setting, economic planning, project execution, and port infrastructure development. 1.INTRODUCTION Transportation, especially maritime transportation, is crucial for economic development. Therefore, the emphasis on improving naval transportation is critical for nations that depend on a strong transportation infrastructure for economic success. The legal status of the Caspian Sea changed following the dissolution of the Soviet Union in 1991, resulting in the emergence of five bordering countries: Russia, Azerbaijan, Kazakhstan, Iran, and Turkmenistan. This change drastically transformed the area's geopolitical structure. The rich resources and commercial appeal of the Caspian Sea have led neighboring countries to strive for benefits from it due to its important historical status. Economic factors have a significant impact on employment, trade, and political relationships in the Caspian Sea region. The growing cooperation among cross-border ecosystems has resulted in the emergence of fresh frontiers in the region, as global entities such as the US, EU nations, and China compete for a greater share in the business sector using diverse strategies. This research concentrates on recognizing the economic variables and evaluating their impact on maritime transportation in the Caspian Sea for bulk and container shipments. These economic factors have an impact on the development strategies of security cooperation in the Caspian Sea region. Due to the cost efficiency of sea transportation for bulk and container shipments compared to other methods, maximizing profits from imports and exports is crucial by fully utilizing economic opportunities. Hence, it is imperative to analyze regional markets to understand how economic factors affect sea transport. This could also assist nations such as Iran in expanding into new markets and boosting their profits. Yousefi (2019) examined the geopolitical significance of countries surrounding the Caspian Sea, with a specific focus on Iran in her research. She highlighted Iran's strategic location between the energy-rich Persian Gulf and the Caspian Sea, emphasizing the influence of factors like nationality, population, and economy on the region's new geopolitics. Motallebi and Kafili (2020) examined strategies to enhance Iran's maritime transport by analyzing its SWOT and identifying weaknesses in both internal and external performance. Their recommendations included forming alliances, making significant investments, and prioritizing the private sector to boost the capacity of the maritime fleet. Rasekhi et al. (2021) analyzed Iran's trade capabilities with CIS member nations, assessing the resemblance of Iran's trade patterns with the region using different trade measures, and found that Iran has utilized under 10% of its trade capacity in the majority of CIS nations. Ismailzade and Babayev (2020) highlighted the advantages of the Caspian Sea basin transportation networks for major powers like US, EU, China, and Russia, noting the cost and time-saving opportunities of this corridor. In the study of shipping and logistics management, Lun et al. (2010) discussed different facets of shipping and logistics, focusing on the close connection between international trade and transportation, particularly sea transport. Additionally, they discussed features of the shipping industry, pricing system for shipping, and various categories of maritime transport such as bulk and container, liner and Trump shipping networks, container supply chain, port activities, flexible ports, and more. 2. MATERIALS AND METHODS The focus of the research is on the countries surrounding the Caspian Sea, including Iran, Russia, Azerbaijan, Kazakhstan, and Turkmenistan. Data from 2014 to 2024 in key ports was analyzed, with population, GDP, CPI, and trade volume as independent variables and sea transportation volume as the dependent variable. Forecasting what lies ahead is crucial for countries to make decisions that influence their future possibilities during periods of economic and political instability. Forecasting the amount of maritime transportation can help in making informed decisions about trade adjustments and economic and political links in the maritime industry. The regression model is an important tool for examining data and predicting upcoming outcomes. The findings indicated that the group with the strongest correlation has a significant impact on the level of maritime transportation in the Caspian Sea. Regression equations were developed to forecast the fluctuations in the dependent variable by examining changes in the independent variables to gain insight into their influence. 3.RESULTS The findings show that the population, acting as the sole independent variable, influences the level of sea transportation in the Caspian coastal nations through social, economic, and political factors. The population variable change will result in a significant difference in maritime transport volume. The regression model suggests that the increase in population significantly boosts maritime transport volume, making population a crucial factor influencing countries' decisions on economic policies, as well as political and diplomatic relations with other nations. Still, the issue at hand is why is there a strong and positive correlation between using CPI to measure PPP and the amount of sea transportation in a country like Iran. 4. DISCUSSION AND CONCLUSION The findings indicate that the demographic changes in the countries studied have a significant impact on the volume of sea transportation, as evidenced by a strong correlation. Additionally, the amount of maritime traffic in Iranian ports along the Caspian Sea fluctuates at a rate of 1:92 by shifts in population. Essentially, with each additional one million people in the population, the volume of bulk and container transportation in the ports of this area increases by around two million tons. Consequently, there is a boost in CPI, resulting in enhanced economic prosperity by raising the PPP of typical households and subsequently increasing societal contentment. Research results demonstrate the impact of population growth on the quantity of maritime shipping and the demand for trade to deliver essential products through imports. Hence, to reach the maximum capacity, it is essential to identify strengths and weaknesses, regional opportunities and threats, and take strategic measures such as expanding the fleet, enhancing the container fleet and communication infrastructure, boosting economic collaboration, dedicating a portion of GDP to maritime economic activities, and more. Refrences: Ismailzade, F. and Babayev, B., 2020. Strategic Advantages of Transport Network in the Caspian Sea Region. Development of Management and Entrepreneurship Methods on Transport, 4(73), pp.79-91. https://doi.org/10.31375/2226-1915-2020-4-79-91. Motallebi, MA. and Kafili, V., 2020. The Strategies of Developing Iran's Maritime Transport. Quarterly of Defense Economics & Sustainable Development, 5(17), pp.159-178. https://dorl.net/dor/20.1001.1.25382454.1399.5.17.6.4. (In Persian) Rasekhi, S., Saedi, R., Yadmellat, N. and Hoseini, S.A., 2021. Trade Potentials of Iran and CIS. Journal of International Marketing Modeling, 2(1), pp.18–30. https://www.doi.org/10.22080/jimm.2021.20981.1015. Lun, Y., Lai, K. and Cheng, T., 2010. Shipping and Logistics Management. London: Springer. https://doi.org/10.1007/978-1-84882-997-8. Yousefi, A., 2019. The Study of Caspian Sea Geopolitical Importance. Scientific Quarterly of the Iranian Geographical Society, 17(62). pp.206-217. (In Persian) اهمیت و موقعیت ژئوپلیتیک دریای خزر در منطقه خاورمیانه، آسیای میانه، اروپا و قفقاز، در زمینه تجارت و حمل‌و‌نقل، نیازمند توسعه تعاملات نزدیک اقتصادی و سیاسی منطقه‌ای و فرا‌منطقه‌ای می‌باشد. عوامل سیاسی و اقتصادی، راهبردهای توسعه همکاری‌های امنیتی و اقتصادی در منطقه دریای خزر را شکل می‌دهد. جهت افزایش سهم جمهوری اسلامی ایران از منابع و منافع دریای خزر، شاخص‌های اقتصادی در بازه زمانی 2014 تا 2024 را در پژوهش حاضر مورد شناسایی قرار داده و به ارزیابی و تحلیل تاثیر این شاخص‌ها بر حمل‌و‌نقل دریایی در دریای خزر پرداخته‌ایم. داده‌های مورد استفاده از پایگاه‌های اطلاعاتی سازمان ملل متحد، بانک جهانی و سازمان بنادر و دریانوردی جمهوری اسلامی ایران جمع‌آوری شده‌اند. برای ارزیابی تاثیر شاخص‌های انتخابی از روش آماری رگرسیون استفاده کرده‌ایم. یک معادله رگرسیونی برای ارزیابی میزان اثرپذیری حمل‌و‌نقل دریایی در دریای خزر از شاخص‌های اقتصادی منتخب در کشورهای موضوع پژوهش به دست آورده‌ایم. یافته‌های پژوهش بیانگر این مهم است که چگونه روند کاهش یا افزایش جمعیت کشورها، تولید ناخالص داخلی و حجم تجارت آن‌ها بر حجم حمل‌و‌نقل دریایی و نیاز به معاملات تجاری برای تامین نیازهای اساسی یک کشور از طریق واردات و صادرات تاثیرگذار خواهد‌بود. براساس نتایج به‌دست آمده، اقدامات و راهبردهای هوشمندانه با بهره‌گیری از پیش‌بینی‌های صورت گرفته در خصوص شناسایی و ارزیابی شاخص‌های اقتصادی موثر بر حمل‌و‌نقل دریایی، می‌تواند به هدف‌گذاری، برنامه‌ریزی‌های کوتاه‌مدت و بلندمدت اقتصادی، اجرای پروژه‌های توسعه دریامحور و توسعه زیرساخت‌های بندری کمک شایان توجهی نموده و در نتیجه منجر به رونق اشتغال‌آفرینی، ارتقاء سطح رفاه اجتماعی حاصل از سرمایه‌گذاری‌های داخلی و خارجی و ثبات اقتصادی گردد.

https://jmst.kmsu.ac.ir/article_209647_3cfd1375152663cc5aab7562d189ffd8.pdf

انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2026 01 21 Evaluation and Ranking of Global Megatrends Affecting Sea Power Using a Fuzzy Screening System ارزیابی و رتبه‌بندی کلان‌روندهای جهانی مؤثر بر قدرت دریایی با استفاده از سامانه غربال‌گری فازی 30 46 235133 10.22113/jmst.2025.502198.2627 FA صفر فضلی گروه آینده‌پژوهی، دانشکده علوم اجتماعی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران. علی نیکنام گروه آینده‌پژوهی، دانشکده علوم اجتماعی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران. 0009-0009-7334-3454 Journal Article 2025 01 30 ABSTRACT Whoever rules the waves rules the world." Global megatrends pose significant challenges to the sea power of nations, affecting critical areas such as food security, energy, economy, and overall national stability. Failure to prioritize and identify the most impactful megatrends may lead to inefficient allocation of resources—financial, human, and temporal—toward trends with limited relevance to sea power. This study aims to facilitate the identification and analysis of global megatrends by ranking them based on their influence on various dimensions of sea power. Employing an applied and qualitative research approach, data were collected through documentary and field studies, utilizing computer files and questionnaires sourced from reputable textual references and domain experts. The primary analytical method applied was the Yager Fuzzy Screening System. A comprehensive review of multiple sources resulted in the identification of ten global megatrends and eleven dimensions of sea power, encompassing 52 components. These factors were then evaluated by experts using the fuzzy screening system. The final analysis highlighted four megatrends as having the greatest impact on sea power: climate change and environmental pressures, technological advancements and connectivity, technological disruptions and societal concerns, and social and economic changes. The remaining megatrends were ranked accordingly in subsequent positions. INTRODUCTION The evolving global landscape presents a myriad of megatrends that significantly challenge the maritime power and overall security of nations. Reputable international organizations have identified numerous critical global megatrends. However, without a systematic approach to prioritize and select those with the highest impact, maritime strategic planning may inadvertently direct valuable resources—financial, human, and temporal—toward trends of marginal relevance. This research is designed to analyze and identify the global megatrends that most substantially influence maritime power by ranking them according to their impact on key dimensions of sea power. The primary research question addressed is: Which subset of global megatrends exerts the greatest influence on maritime power? Secondary inquiries focus on elucidating the fundamental elements of these megatrends as well as the specific dimensions and components that constitute maritime power. MATERIALS AND METHODS Adopting an applied and qualitative research approach, this study utilized both documentary and field-based data collection methods. Data were gathered through computer-assisted tools and structured questionnaires. The identification of global megatrends, along with the dimensions and components of maritime power, was accomplished through an extensive review of credible textual sources and further refined via interviews with domain experts. These experts were also invited to identify any potentially overlooked trends, dimensions, or components. A fuzzy screening system served as the primary analytical tool. In this system, global megatrends were treated as candidate variables, while the dimensions of maritime power functioned as evaluation criteria—thereby eliminating the necessity for traditional statistical tests. Ten experts were selected through snowball sampling, and a questionnaire featuring a curated list of megatrends and maritime power dimensions (with concise descriptions) was administered. Experts evaluated these elements using linguistic scales, and the subsequent analysis was performed through the fuzzy screening system. RESULTS An analysis of reports published in 2023 and 2024, combined with expert consultations, resulted in the identification of ten global megatrends: 1. Global and regional power rivalries 2. Population pressures and migration 3. Climate change and environmental pressures 4. Technological advancements and connectivity 5. Economic shifts and energy transition 6. Inequality and governance challenges 7. Globalization gaps and fractured societies 8. Comprehensive health and well-being 9. Technological disruptions and societal concerns 10. Social and economic changes Similarly, an initial list comprising eleven dimensions of maritime power was compiled: 1. Maritime sciences 2. Industries and infrastructures 3. Maritime fleets 4. Maritime services 5. Geopolitical capacities and dimensions 6. Military sea power 7. Human resources 8. Intelligence and soft power 9. Operational capabilities 10. Geographic positioning 11. Support structures Utilizing the fuzzy screening system, the ten global megatrends were ranked based on their impact on these maritime dimensions. The highest impact was attributed to: Climate change and environmental pressures Technological advancements and connectivity Technological disruptions and societal concerns Social and economic changes Following these, a second tier was established, including: Global and regional power rivalries Population pressures and migration Economic shifts and energy transition Inequality and governance challenges Globalization gaps and fractured societies The megatrend of comprehensive health and well-being was positioned in the third tier. DISCUSSION AND CONCLUSION The application of the fuzzy screening system in this study facilitated a systematic ranking of ten global megatrends based on their influence on maritime power dimensions. The results corroborate findings from key international reports, such as the United Nations' Review of Maritime Transport 2024, which emphasizes environmental, operational, geopolitical, technological, and economic factors as pivotal to the performance and sustainability of maritime transport (United Nations, 2024). Similarly, the Global Maritime Trends 2050 report by Lloyd’s Register Foundation and Economist Impact (2023) highlights the critical role of climate change collaboration and rapid technology adoption in shaping the maritime sector's future. These reports align closely with the top-ranked megatrends identified in this research. Furthermore, Allahverdizadeh and Karimi (2022) titled A New Approach to the Theory of Maritime Power in the 21st Century (During Peace and War), discusses the dynamic evolution of maritime power by focusing on emerging threats, environmental changes, economic dynamics, and the roles of state and non-state actors.These aspects are consistent with the megatrends identified in our study, particularly climate change and environmental pressures and social and economic changes, while globalization gaps and fractured societies were found to exert a moderate influence in the current analysis. This study addresses a notable research gap by prioritizing global megatrends based on their impact on maritime power dimensions. Its methodological framework and contemporary scope contribute significantly to the literature. Future research may explore each identified megatrend in greater detail and examine its implications for maritime power more comprehensively, potentially utilizing additional multi-criteria decision-making techniques such as fuzzy ANP or fuzzy AHP. Policymakers in the maritime domain can leverage these findings to refine strategic planning and resource allocation. ACKNOWLEDGEMENT The authors gratefully acknowledge the editorial board and reviewers of the Journal of Marine Science and Technology for their invaluable insights, which greatly contributed to the refinement and quality of this study. REFERENCES Allahverdizadeh, R. and Karimi, M., 2022. A New Approach to the Theory of Seapower in the 21st Century (In Times of War and Peace). International Geopolitics Quarterly, 18, pp. 383-411. https://journal.iag.ir/article_145524.html Lloyd's Register Foundation; Economist Impact. 2023. Global Maritime Trends 2050. Pp. eds.https://impact.economist.com/ocean/global-maritime-trends-2050/downloads/Global%20Maritime%20Trends%202050%20Report.pdf https://doi.org/10.60743/xrta-z334 United Nations. 2024. Review of maritime transport 2024. Pp. eds. United Nations Publications, New York. https://unctad.org/system/files/official-document/rmt2024_en.pdf هرکه می‎خواهد بر دنیا حکومت کند باید دریا را در سیطره قدرت خود داشته باشد. روندهایی در سطح جهانی با تأثیر بر قدرت دریایی کشورها، امنیت غذایی، انرژی، اقتصاد و به طور کلی موجودیت آن‌ها را تهدید می‌کند. بدون اولویت‌بندی و انتخاب کلان‌روندهای با تأثیر بیشتر، احتمال آن وجود دارد که منابع موجود مالی، انسانی، زمان و غیره صرف مطالعه و تحلیل روندهایی شود که تأثیر چندانی بر مسئله ندارند. این پژوهش با هدف کمک به تحلیل و شناسایی کلان‌روندهای جهانی از طریق رتبه‌بندی آن‌ها بر اساس تأثیرشان بر ابعاد قدرت دریایی انجام می‌شود. این پژوهش از نوع کاربردی و کیفی می‌باشد. داده‌ها از نوع کیفی بوده و به دو روش اسنادی و میدانی با ابزار فایل‌های رایانه‌ای و پرسشنامه از منابع معتبر متنی و خبرگان جمع‌آوری شده‌اند. روش محوری تجزیه و تحلیل داده‌ها سامانه غربال‌گری فازی است. با بررسی منابع مختلف، فهرستی از ده کلان‌روند جهانی و یازده بعد قدرت دریایی مشتمل بر پنجاه و دو مؤلفه احصاء شده است. این کلان‌روندها و ابعاد در اختیار خبرگان قرار گرفته و طی سامانه غربال‌گری فازی رتبه‌بندی شدند. در آخر چهار کلان‌روند «تغییرات اقلیمی و فشار بر محیط زیست»، «پیشرفت‌های فناوری و اتصال»، «شگفتی‌های فناوری و نگرانی‌های اجتماعی» و «تغییرات اجتماعی و اقتصاد» بر اساس تأثیرشان بر قدرت دریایی در رتبه اول و باقی کلان‌روندها در رتبه‌های بعدی قرار گرفتند. در بررسی ادبیات موضوع، پژوهشی یافته نشد که به اولویت‌گذاری کلان‌روندهای جهانی بر پایه ابعاد قدرت دریایی پرداخته باشد؛ بنابراین، مسئله پژوهش حاضر در کنار روش تجزیه‌وتحلیل داده‌ها و افق زمانی داده‌های آن از سهم‌یاری‌های آن به شمار می‌آید.

https://jmst.kmsu.ac.ir/article_235133_dfec97931c972062a880ba24a1e479c2.pdf

انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2025 12 22 Recognition of fuzzy features of drainage network using GeoEye-1 satellite imagery (Case study of Lahijan River) بازشناسی ویژگی‌های فازی شبکه آب‌ها با استفاده از تصاویر ماهواره‌ای GeoEye-1 (مطالعه موردی رودخانه لاهیجان) 47 59 170396 10.22113/jmst.2022.328810.2466 FA هیوا علمیزاده گروه زمین شناسی دریایی، دانشکده منابع طبیعی دریا، دانشگاه علوم و فنون دریایی خرمشهر، خرمشهر، ایران. هادی مهدی پور دفتر اصلی نوآوری، مؤسسه سیننتا، آلمریا، اسپانیا. Journal Article 2022 02 12 ABSTRACT This study aims to automatically recognize drainage network patterns in a part of the Lahijan River using high-resolution panchromatic satellite imagery (HR-PRS) and fuzzy clustering algorithms. This study evaluates the performance of these methods in segmenting GeoEye-1 satellite images for detecting geomorphic features and drainage networks. After radiometric and geometric preprocessing, fuzzy segmentation of HR-PRS panchromatic images was performed using FWS, MSA, IDF, and CFM algorithms in MATLAB software. Fuzzy clustering algorithms were applied to the input HR-PRS images. The results show that the CFM (Classical Fusion Method and FCM) algorithm achieves superior performance in fuzzy segmentation and feature detection. This algorithm reduces segmentation errors caused by spectral feature overlap between classes and identifies spatial phenomena and clusters of various sizes, shapes, and densities, resulting in well-defined image boundaries. This superior performance is attributed to the use of fuzzy numbers and efficient clustering methods. Remote sensing technology provides multi-temporal imagery, offering a suitable foundation for monitoring environmental changes, detecting features, and accurately extracting information. The use of clustering algorithms and fuzzy features represents an optimal method for integrating information from HR-PRS satellite images for segmentation purposes. 1. INTRODUCTION In recent decades, significant progress has been made in using multi-temporal, high-resolution satellite data as an important data source for detecting and monitoring land surface features and phenomena. Remote sensing technology provides new opportunities for studying the spatial organization of landscapes and drainage network characteristics due to its ability to acquire information under different climatic conditions, its multi-temporal and multi-spectral imaging capabilities, data availability, and increasing spatial and temporal resolution (Benincasa et al., 2019). Access to high-resolution panchromatic images enables automatic processing without human intervention for studying, identifying, and monitoring features, as well as classifying landforms (Chang et al., 2015; Wang et al., 2018). The presence of obstacles such as cloud cover and shadows is one of the most common sources of error in remote sensing imaging, causing confusion and misclassification in land surface information extraction (Swetnam et al., 2018; Jurado et al., 2020). Therefore, image segmentation is usually modeled as a clustering process or unsupervised classification. The advantages of image segmentation include algorithm simplicity, the ability to model, the elimination of uncertainty effects, and high implementation speed. Recent research indicates increasing use of fuzzy clustering algorithms for segmenting high-resolution panchromatic images in digital remote sensing image processing, with acceptable performance (Adachi et al., 2017; Hua, 2017; Arai et al., 2018). This paper aims to automatically recognize formal patterns of the drainage network using HR-PRS images and fuzzy clustering algorithms, while evaluating their performance in segmenting GeoEye-1 satellite images for detecting geomorphic features in the study area. 2. MATERIALS AND METHODS Fuzzy segmentation using clustering algorithms and remote sensing techniques was applied to a part of the Lahijan River. The study area was selected due to its location in an area with human settlements and agricultural textures, offering good separability and diverse spatial and radiometric criteria. GeoEye-1 satellite panchromatic images with a spatial resolution of 0.5 meters were used, acquired from an altitude of 681 km. After radiometric and geometric pre-processing, fuzzy segmentation was performed using FWS, MSA, IDF, and CFM algorithms in MATLAB software (Bayram et al., 2018). For fuzzy clustering, input triangular fuzzy numbers for clustering in p dimensions were defined as x̃_k = {x̃_{k,1}, …, x̃_{k,p}} for k = 1, …, n (where n is the number of image pixels, p = 1). Cluster centers were represented as ṽ_i = {ṽ_{i,1}, …, ṽ_{i,p}} for i = 1, …, c (where c = 4 clusters). The processing was performed in four stages with parameters l_Max, θ > 1, K ≥ 0, and initial values for m_{ṽ_{i,j}}^{(0)}. The membership degrees u_{i,k}^{(l)} and cluster centers were iteratively updated until convergence. Defuzzification was then applied, assigning each pixel to the cluster with the highest membership degree, thereby producing the segmented image with clearly defined region boundaries. To improve fuzzy segmentation performance, digital number (DN) values and textural features (contrast, entropy, energy, and homogeneity from the GLCM matrix) were used alongside radiometric features (Ben Salah et al., 2010). 3. RESULTS The FWS, CFM, IDF, and MSA algorithms were applied for fuzzy clustering and segmentation of HR-PRS panchromatic images in the study area. Performance was evaluated using three indicators: 1. Spatial indicator: Accurate detection of the river boundary and its distinction from surrounding features. 2. Spatial indicator: Correct detection of human settlement textures. 3. Spatio-radiometric indicator: Main and sub-boundaries between agricultural fields. The CFM algorithm showed excellent performance in assigning pixels to different clusters and in finding optimal cluster numbers and centers. Image boundaries were well detected, and the algorithm provided higher accuracy in identifying clusters of various shapes, sizes, and densities, as well as in detecting spatial features. The CFM method performed best in the first indicator (river detection and distinction of drainage network boundaries from the surrounding environment). The IDF (Interval-valued Data Fuzzy c-means) method, which incorporates image uncertainty, performed second best after CFM for all three indicators. The MSA (Mean-Shift Algorithm) showed good performance in the first indicator and, along with IDF, showed the best performance in detecting rural settlement textures compared to the other methods. 4. DISCUSSION AND CONCLUSION The results confirm the effectiveness of fuzzy clustering algorithms for segmenting multispectral remote sensing images and validate the performance of the proposed segmentation methods for detecting spatial features and accurately extracting information from images. In accordance with the research results, using clustering algorithms and fuzzy features is an optimal method for integrating information from HR-PRS satellite images of a geographical area for segmentation purposes. Although no single method can be considered optimal in every respect or for every indicator, depending on the images, the geographical area, and the intended application, different algorithms may perform optimally. Combining the investigated algorithms in future research using Gaussian fuzzy numbers and GG-FCM clustering with fuzzy parameters could lead to an efficient method suitable for various geographical areas. Gaussian fuzzy numbers are the most suitable type for image segmentation using HR-PRS images, and the use of fuzzy numbers in general can lead to better results. Given the favorable characteristics of fuzzy clustering algorithms, including robustness to noise and outliers, the use of Gaussian fuzzy features and fuzzy clustering methods based on Fuzzy C-Means (FCM) constitutes one of the most effective approaches for segmentation. Furthermore, the application of various types of fuzzy numbers and different metrics, as well as the fuzzification of membership degrees and distance parameters, can lead to optimal and desirable performance for more robust fuzzy clustering. ACKNOWLEDGEMENT We would like to thank Khorramshahr University of Marine Science and Technology for supporting this work under research grant contract No. 160. REFERENCES Adachi, M., Ito, A., Yonemura, S. and Takeuchi, W., 2017. Estimation of global soil respiration by accounting for land-use changes derived from remote sensing data. Journal of Environmental Management, 200, pp.97-104. https://doi.org/10.1016/j.jenvman.2017.05.076 Arai, R., Kodaira, S., Takahashi, T., Miura, S. and Kaneda, Y., 2018. Seismic evidence for arc segmentation, active magmatic intrusions and syn-rift fault system in the northern Ryukyu volcanic arc. Earth, Planets and Space, 70(1). https://doi.org/10.1186/s40645-017-0157-2 Bayram, B., Demir, N., Akpinar, B., Oy, S., Erdem, F., Vögtle, T. and Seker, D.Z., 2018. Effect of Different Segmentation Methods Using Optical Satellite Imagery to Estimate Fuzzy Clustering Parameters for SENTINEL-1A SAR Images. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLII-1, pp.39-43. https://doi.org/10.5194/isprs-archives-XLII-1-39-2018 Ben Salah, M., Mitiche, A. and Ben Ayed, I., 2010. Effective level set image segmentation with a kernel induced data term. IEEE Transactions on Image Processing, 19, pp.220-232. https://doi.org/10.1109/tip.2009.2032940 Benincasa, M., Falcini, F., Adduce, C., Sannino, G. and Santoleri, R., 2019. Synergy of Satellite Remote Sensing and Numerical Ocean Modelling for Coastal Geomorphology Diagnosis. Remote Sensing, 11(22), p.2636. https://doi.org/10.3390/rs11222636 Chang, N.B., Bai, K. and Chen, C.-F., 2015. Smart information reconstruction via time-space-spectrum continuum for cloud removal in satellite images. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8(5), pp.1898-1912. https://doi.org/10.1109/JSTARS.2015.2400636 Hua, A.K., 2017. Land Use Land Cover Changes in Detection of Water Quality: A Study Based on Remote Sensing and Multivariate Statistics. Journal of Environmental and Public Health, 2017, pp.1-12. https://doi.org/10.1155/2017/7515130 Jurado, J.M., Cárdenas, J.L., Ogayar, C.J., Ortega, L. and Feito, F.R., 2020. Semantic Segmentation of Natural Materials on a Point Cloud Using Spatial and Multispectral Features. Sensors, 20(8), p.2244. https://doi.org/10.3390/s20082244 Swetnam, T.L., Gillan, J.K., Sankey, T.T., McClaran, M.P., Nichols, M.H., Heilman, P. and McVay, J., 2018. Considerations for Achieving Cross-Platform Point Cloud Data Fusion across Different Dryland Ecosystem Structural States. Frontiers in Plant Science, 8. https://doi.org/10.3389/fpls.2017.02144 Wang, T., Yan, G., Mu, X., Jiao, Z., Chen, L. and Chu, Q., 2018. Toward operational shortwave radiation modeling and retrieval over rugged terrain. Remote Sensing of Environment, 205, pp.419-433. https://doi.org/10.1016/j.rse.2017.11.006 هدف این پژوهش بازشناسی خودکار الگو‌های فرمیک شبکه آبراهه‌ها در بخشی از رودخانه لاهیجان با استفاده از تصاویر پنکروماتیک با توان تفکیک مکانی بالا (HR-PRS) و الگوریتم‌های خوشه‌بندی فازی است و کارایی این روش‌ها را در ناحیه‌بندی تصاویر ماهواره‌ای GeoEye-1 محدوده مورد مطالعه به منظور تشخیص و آشکارسازی عوارض ژئومورفیکی و شبکه آبراهه‌ها مورد بررسی قرار می‌دهد. در این راستا ناحیه‌بندی فازی تصاویر پانکروماتیک HR-PRS محدوده مورد مطالعه، پس از پیش‌پردازش‌های رادیومتریک و هندسی با استفاده از الگوریتم‌های FWS ، MSA ، IDF و CFM ، در نرم‌افزار MATLAB صورت گرفت. در نهایت الگوریتم‌های خوشه‌بندی فازی مورد بررسی که دارای پارامترهای فازی هستند، بر روی تصاویرHR-PRS ورودی اعمال شده و نتایج آن مورد بحث و بررسی قرار گرفته است. نتایج نشان می‌دهد الگوریتم خوشه‌بندی Classical Fusion Method and FCM (CFM) در زمینه ناحیه‌بندی فازی و آشکارسازی شاخص‌های مورد بررسی بهترین عملکرد را دارا می‌باشد. همچنین این الگوریتم می‌تواند اشکالات ناحیه‌بندی ناشی از همپوشانی ویژگی‌های طیفی بین طبقات نتایج خوشه‌بندی را کاهش و بهبود دهد و پدیده‌های مکانی و خوشه‌های با انواع اندازه، شکل و چگالی را به خوبی شناسایی نماید؛ در نتیجه مرزهای تصویر به خوبی آشکار می‌شوند. دلیل این امر استفاده از اعداد فازی و نیز روش‌های خوشه‌بندی کارا در این روش‌ می‌باشد. این نتایج همچنین نشان‌ می‌دهد تکنولوژی سنجش از دور با ارائه‌ی تصاویر چندزمانه، می‌تواند مبنای بسیار مناسبی برای پایش و آشکارسازی تغییرات محیطی، تشخیص عوارض و استخراج دقیق اطلاعات از تصاویر باشد و استفاده از الگوریتم‌های خوشه‌بندی و ویژگی‌های فازی، روش مناسب و بهینه جهت ادغام اطلاعات تصاویر ماهواره‌ای HR-PRS از یک منطقه جغرافیایی با هدف ناحیه‌بندی می‌باشد.

https://jmst.kmsu.ac.ir/article_170396_7fc05e8a6e46d62cfd796463ca646f31.pdf

انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2026 01 21 Evaluation of environmental effects of urban solid waste disposal in Babolsar beach, Mazandaran province ارزیابی اثرات زیست محیطی دورریزی پسماندهای جامد شهری در ساحل بابلسر، استان مازندران 60 77 244370 10.22113/jmst.2023.397212.2526 FA آرزو قاسمی گروه آب شناسی و زمین شناسی زیست محیطی، دانشکده علوم زمین، دانشگاه صنعتی شاهرود، شاهرود، ایران. گیتی فرقانی تهرانی گروه آب شناسی و زمین شناسی زیست محیطی، دانشکده علوم زمین، دانشگاه صنعتی شاهرود، شاهرود، ایران. رحیم باقری گروه آب شناسی و زمین شناسی زیست محیطی، دانشکده علوم زمین، دانشگاه صنعتی شاهرود، شاهرود، ایران. Journal Article 2023 05 13 Abstract The purpose of the present study is to assess the environmental impacts of municipal solid waste disposal on Babolsar beach, Mazandaran Province, and its effects on the adjacent soils. For this purpose, 15 surface soil samples and 10 leachate samples were collected and analyzed using standard methods. The concentrations of major and trace elements in soil and leachate samples were measured by ICP-OES and ICP-MS instruments, respectively. The obtained results indicate that the concentrations of Ag and Cu in all studied soil samples, and those of Mn and Ni in most samples, were higher than the world soil average composition. The average values of the elements' enrichment factors followed this trend: Ag (12.6) > Ni (6.3) > Mo (6.2) > Cu (5) > Cd (4.7) > As (4.5) > Cr (3.5) > Pb (3.2) > Co (2.6) > Mn (2) > Fe (1.9) > Zn (1.5). The concentrations of Cd, Co, Cr, Fe, and Ni in leachate samples were higher than the permissible values for leachate disposal into surface and groundwater resources. The obtained results in the present study show that waste disposal management in the study area is a necessity according to environmental guidelines, which may prevent the pollution of soil, plants, and water resources in adjacent areas. 1. INTRODUCTION During the last decades, the excessive growth of the population and the development of urbanization have caused the emergence of various environmental problems. The disposal of produced municipal solid wastes in urban areas is a significant challenge that needs proper environmental management (Wang et al., 2009; Aydi et al., 2013). Site selection for waste disposal is considered the most important step in waste management (Uyan, 2014), since improper disposal of waste will eventually result in soil and water resource pollution, which is mainly due to the production of extremely polluted leachates in disposal sites (Gottschall et al., 2009). The leachate composition is highly complex and contains numerous dissolved and suspended organic/inorganic pollutants such as NH₄⁺, Ca²⁺, Mg²⁺, Na⁺, K⁺, Fe, SO₄²⁻, Cl⁻, NO₃⁻, PO₄³⁻, and potentially toxic elements (e.g., Cd, Cr, Cu, Pb, Ni, and Zn) as well as pathogenic agents (Ogundiran and Afolabi, 2008; Kassasi et al., 2008). Due to the presence of toxic organic and inorganic pollutants in waste leachate, waste disposal sites in urban areas can be a major threat to soil and water resources (Christensen et al., 1992; Chofqi, 2004; Claudio et al., 2006). In Babolsar city, a high amount of municipal waste is produced daily and is disposed of near the beach without environmental considerations. The humid weather of the area leads to the production of a large amount of waste leachate, which can infiltrate into the Caspian Sea and groundwater resources and may cause severe pollution of the coastal area and marine ecosystem. On the other hand, soil pollution in the area is worrying due to the expansion of agricultural lands around the landfill site. The objective of the present study is to assess the level of soil pollution in this area and to investigate the chemical composition of solid waste leachate. 2. MATERIALS AND METHODS Fifteen topsoil samples (0–15 cm depth) were collected using a stainless steel shovel. The soil samples were dried at room temperature for 48 hours. Then, the samples were passed through a 10-mesh sieve and pulverized using an agate mortar until the particle size reached up to 75 microns. The concentrations of major and trace elements in powdered soil samples were measured by an ICP-MS instrument (Perkin 9000 DRCE model) after strong acid digestion (HF+HCl+HNO₃+HClO₄). To evaluate the accuracy of the data, blank samples and reference materials were analyzed, and to check the precision of the analytical results, triplicate analyses of target elements in each sample were carried out. In order to quantitatively evaluate the level of soil pollution around the Babolsar waste disposal site, some geochemical indices including Enrichment Factor (EF), Pollution Index (PI), and Pollution Load Index (PLI) were calculated. The pH and EC values of the leachate samples were recorded in the field using a portable pH-EC meter. Ten leachate samples were collected in 1.5-litre polyethylene bottles. In each sampling site, two subsamples were collected: one for measuring the concentration of potentially toxic elements and the other for determining the physicochemical parameters. Before sampling, the bottles were rinsed with leachate. The first subsamples were filtered through a 0.45-micron filter paper, and the pH was reduced to less than 2 by adding a few drops of dilute HNO₃. The concentration of potentially toxic elements was measured by an ICP-MS device immediately after sample preparation. The second subsamples were used without any preparation to measure total dissolved solids (TDS) and total suspended solids (TSS) using the gravimetric method. 3. RESULTS AND DISCUSSION The concentrations of Ag and Cu in all studied soil samples and the concentration of Mn and Ni in most samples were higher than the world soil average composition. The concentrations of Co, Cr, Fe, Mo, Pb, Cd, and As in some soil samples were higher than their values in the world soil average composition. The Zn concentration in all samples was lower than its average value in world soils. On the basis of enrichment factor values, the studied soils were highly enriched in Ag, Ni, and Mo, and moderately enriched in Cu, Cd, As, Cr, Pb, and Co. There was a low enrichment of soils in Mn, Fe, and Zn. The pollution index values of Ag, Cu, Mn, and Mo were higher than 1, indicating a probable anthropogenic source of these elements in the soil. The calculated pollution load index values also showed average soil pollution in the study area. Based on the obtained results, in most leachate samples, the EC value was higher than the maximum allowable limit (1500 µs/cm). The amounts of TDS and TSS in all samples were higher than the standard values. The concentrations of Al, As, Ba, Cu, Pb, Mn, Se, and Zn in all leachate samples were within the permitted range provided by the World Health Organization for the discharge of landfill leachate into surface waters, while the concentrations of Cd, Co, Cr, Fe, and Ni in some samples were higher than their respective values in the WHO standard. According to the degree of pollution (Cd), the studied leachate samples were highly polluted. 4. CONCLUSION The results of the present study show that improper disposal of municipal wastes on Babolsar beach may cause serious environmental issues for the surrounding environment and local residents. The infiltration of municipal leachate may reduce the quality of water resources and soils. Therefore, the reduction of leachate production before waste disposal is deemed necessary. In general, it is of crucial importance to select a suitable site for sanitary waste disposal to prevent leachate leakage and the release of pollutants into water resources and soil. هدف از انجام این پژوهش، بررسی ترکیب شیمیایی شیرابه محل دفن زباله پسماندهای جامد شهری دورریزی شده در ساحل بابلسر، استان مازندران، و ارزیابی آلودگی خاک پیرامون محل دفن زباله است. بدین منظور تعداد 10 نمونه شیرابه زباله و 15 نمونه خاک سطحی از پیرامون محل دورریزی زباله برداشت شد. پس از آماده‌سازی نمونه‌ها، غلظت عناصر اصلی و جزئی در نمونه‌های خاک، توسط دستگاه ICP-OES، و غلظت عناصر بالقوه سمی در نمونه‌های شیرابه، توسط دستگاه ICP-MS اندازه‌گیری شد. نتایج بدست آمده نشان می‌دهد که غلظت عناصر نقره و مس در تمام نمونه‌های خاک، و غلظت منگنز و نیکل در بیشتر نمونه‌ها در مقایسه با ترکیب میانگین خاک جهانی بیشتر است. میانگین ضریب غنی‌شدگی عناصر مورد مطالعه به ترتیب زیر کاهش می‌یابد: Ag (12.6) > Ni (6.3) > Mo (6.2) > Cu (5) > Cd (4.7) > As (4.5) > Cr (3.5) > Pb (3.2) > Co (2.6) > Mn (2) > Fe (1.9) > Zn (1.5). مقایسه غلظت عناصر بالقوه سمی در نمونه‌های شیرابه با استاندارد استاندارد دفع شیرابه نشان می‌دهد که غلظت عناصر کادمیم، کبالت، کروم، آهن، منگنز و نیکل در برخی نمونه‌ها بیشتر از حد مجاز این عناصر در شیرابه پسماندهای شهری است. با توجه به نتایج بدست آمده در این تحقیق، مدیریت دفن پسماندهای جامد شهری به شکل اصولی و بر اساس موازین زیست‌محیطی، امری ضروری است و از آلودگی منابع آب، خاک، و محصولات زراعی منطقه جلوگیری خواهد کرد.

https://jmst.kmsu.ac.ir/article_244370_b736a5ded6ea197757b071b9960bee67.pdf

انجمن علوم و فنون دریایی مجله علوم و فنون دریایی 2008-8965 24 4 2025 12 22 Numerical Simulation of Resistance and Trim of a High Speed Planing Craft using Computational Fluid Dynamics ‌شبیه‌سازی عددی مقاومت و تریم یک شناور تندرو بدنه پروازی با استفاده از دینامیک سیالات محاسباتی 78 90 120203 10.22113/jmst.2020.219383.2352 FA رضا شمسی گروه مهندسی دریا، کشتی سازی، دانشکده مهندسی دریا، دانشگاه علوم و فنون دریایی خرمشهر، خرمشهر، ایران. علی ابراهیمی گروه مهندسی دریا، کشتی سازی، دانشکده مهندسی دریا، دانشگاه علوم و فنون دریایی خرمشهر، خرمشهر، ایران. Journal Article 2020 02 12 ABSTRACT This study investigates the hydrodynamic performance of a high-speed planing craft from the Naples warped hard chine hull series using Computational Fluid Dynamics (CFD). Numerical simulations were performed by solving the Reynolds-Averaged Navier-Stokes (RANS) equations coupled with the k-ε turbulence model. A three-dimensional, unsteady, two-phase (air-water) turbulent flow was modeled. The vessel was simulated with two degrees of freedom (heave and pitch) to calculate resistance and trim. Dynamic meshing and a six-degree-of-freedom (6-DOF) rigid body solver were employed to couple the fluid flow with the vessel motion. Simulations were conducted for a Reynolds number greater than 3.5×10⁶ and a Froude number range of 0.52 to 1.65. The numerical results for resistance and trim were validated against existing experimental data, showing average errors of less than 3% and 9%, respectively. Additionally, the wave pattern and wake field behind the craft were analyzed at various speeds. The results confirm the high accuracy and capability of the RANS-based CFD method for hydrodynamic analysis of planing vessels. 1. INTRODUCTION Over the past century, significant increases in the speed of transportation vehicles have been observed, except for commercial ships, where hydrodynamic resistance remains the primary limiting factor. This limitation is particularly severe for high-speed vessels. Planing craft operate in three distinct regimes: displacement, transition (semi-planing), and planing. In the planing mode, a significant portion of the vessel's weight is supported by hydrodynamic lift rather than hydrostatic buoyancy, leading to reduced wetted surface area and higher achievable speeds. Due to the complex, two-phase turbulent flow around planing hulls at high speeds, analytical solutions are impractical, and experimental methods are costly and limited. Consequently, Computational Fluid Dynamics (CFD) has emerged as an efficient and powerful tool for such analyses. Previous studies have applied RANS-based simulations to various planing craft configurations, including stepped hulls and tunnels, demonstrating the capability to predict resistance and trim. However, accurate simulation requires careful consideration of dynamic mesh motion and free-surface capturing. This study aims to numerically investigate the hydrodynamic performance of a Naples-series planing craft using a dynamic meshing approach and two-degree-of-freedom motion, validating resistance and trim predictions against experimental data and analyzing the resulting wake and wave patterns. 2. MATERIALS AND METHODS The fluid was assumed incompressible. The governing equations were the unsteady RANS equations for mass and momentum conservation. The standard k-ε turbulence model was employed to model the Reynolds stress tensor. The volume of fluid (VOF) method was used to capture the air-water interface. The studied vessel is a planing craft from the Naples systematic series. Key principal dimensions include: length of 2.611 m, beam of 0.86 m, draft of 0.163 m, mass of 92.25 kg, and longitudinal center of gravity at 1.036 m. The computational domain was sized to prevent wave reflection: the outlet was placed 7.5 ship lengths downstream, and the water depth was 2.5 times the vessel length. A velocity inlet was specified at the inlet, and a pressure outlet at the downstream boundary. The craft was modeled as a symmetric half-body to reduce computational cost, with a symmetry plane applied at the centerline. A critical aspect of the methodology was the mesh strategy. Dynamic meshing was utilized to allow the vessel to move with heave and pitch (2-DOF). An overset mesh (or dynamic mesh region) was created around the hull, which moved with the vessel, while a background mesh remained stationary. To ensure high resolution of the free surface and wake, three refinement blocks with varying thicknesses were defined near the water surface. Additionally, three triangular blocks were placed behind the hull to capture the evolving wake pattern at different speeds. The final mesh consisted of approximately 991,671 cells after a grid independence study. Boundary layer resolution was ensured with eight prism layers around the hull. A time step of 0.001 seconds was selected following a time-step independence study. Simulations were performed using STAR-CCM+ 13.04 on a 16-core parallel processor. 3. RESULTS The numerical results for total resistance were compared against experimental data for Froude numbers between 0.52 and 1.65 (speeds from 2.5 to 7.5 m/s). The results showed very good agreement. The average error was less than 3%, with a maximum error of 4.1% at the highest speed. The numerical simulation accurately captured the increasing trend of resistance with speed. The dynamic trim angle (the angle between the horizontal and the keel) was calculated at 11 different speeds. The results showed that trim increases with speed in the displacement and transition regimes, reaching a maximum at a Froude number of approximately 1.2. Beyond this point, in the full planing regime, the trim angle begins to decrease. Comparison with experimental data yielded an average error of 8.9%, confirming the capability of the dynamic mesh and 2-DOF approach to predict running attitude. Analysis of the wake field at speeds of 2.5, 4.5, and 7.5 m/s revealed that as speed increases, the wake becomes longer and narrower. The transverse wave length behind the hull increases while the width of the V-shaped wave pattern decreases. This is attributed to the increased velocity of the water jet exiting from under the transom, which concentrates the wake along the centerline. Visualization of the hull bottom at different speeds demonstrated a progressive reduction in the wetted surface area as speed increased. At the lowest speed (displacement mode), the wetted area was maximal. At the highest speed (planing mode), the wetted area was minimal, indicating that the hull is primarily supported by hydrodynamic lift, which reduces frictional resistance. 4. DISCUSSION AND CONCLUSION This study successfully demonstrated the application of RANS-based CFD with dynamic meshing to predict the hydrodynamic performance of a Naples-series planing craft. The key conclusions are as follows: 1. The RANS numerical method coupled with the VOF multiphase model exhibits high capability in simulating the complex, two-phase turbulent flow around high-speed planing hulls. 2. Validation results confirmed that the average error for resistance prediction is below 3%, and for trim prediction is below 9%, indicating good engineering accuracy for practical applications. 3. The use of dynamic meshing and a two-degree-of-freedom (heave and pitch) motion is essential for accurately predicting the dynamic trim and equilibrium position of the vessel. 4. The simulation results effectively captured the physical trends of increased wake length and decreased wake width with increasing speed. The reduction in wetted surface area at higher speeds was also clearly visualized, explaining the reduction in resistance growth rate in the planing regime. 5. Future research should focus on extending this methodology to six-degree-of-freedom motions in irregular waves and investigating the effects of design modifications such as steps and spray rails. در دهه اخیر استفاده از شناورهای بدنه پروازی به علت عملکرد مناسب در سرعت‌های بالا در بخش های تجاری و نظامی بسیار گسترده شده است. به دلیل پیچیده ‌بودن رفتار شناورهای بدنه پروازی، تحلیل عملکرد هیدرودینامیکی آنها از اهمیت خاصی برخوردار است. دینامیک سیالات محاسباتی ابزاری موثر و کارآمد برای تحلیل‌های عددی هیدرودینامیک شناورهای تندرو محسوب می‌گردد. در این تحقیق عملکرد هیدرودینامیکی یک شناور تندرو از سری فرم بدنه ناپل با استفاده از دینامیک سیالات محاسباتی و حل عددی معادلات متوسط‌گیری شده ناویر-استوکس (RANS) مورد بررسی قرار گرفته است. این شبیه‌سازی به صورت سه‌بعدی، با درنظرگرفتن اثر سطح آزاد و جریان توربولانسی انجام شده ‌است. برای محاسبه مقدار مقاومت و تریم، شناور در حالت دو درجه‌ی آزادی درنظر گرفته شده ‌است. همچنین با استفاده از حلگر شش درجه آزادی و با استفاده از مش‌های دینامیکی، معادلات دینامیک جسم صلب با معادلات حاکم بر سیال کوپل شده ‌است. شبیه‌سازی‌های عددی برای محاسبه مقاومت این شناور در محدوده اعداد رینولدز بزرگتر از 106 × 5/3 و در محدوده اعداد فرود 52/0 تا 65/1 صورت پذیرفته و با نتایج آزمایشگاهی موجود اعتبارسنجی گردیده ‌است. مقایسه نتایج عددی و تجربی نشان می‌دهد که مقدار خطای متوسط برای مقاومت و تریم شناور به ترتیب کمتر از 3 درصد و 9 درصد است که دقت روش RANS را تایید می نماید. همچنین الگوی موج‌ و میدان ویک در پشت شناور مورد بررسی و تحلیل قرار گرفت.

https://jmst.kmsu.ac.ir/article_120203_ce882a3574a4615e8d93ad44cc875349.pdf