https://i-jmst.vimaru.edu.vn/index.php/i-jmst/issue/feed 2026-06-30T12:26:01+07:00 Open Journal Systems https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/55 2026-04-13T08:11:48+07:00 Mr. Minh Duc Nguyen duc82nguyen1011@gmail.com Assoc. Prof. Ngoc Tu Tran tutn.dt@vimaru.edu.vn Dr. Van Duyen Pham duyenpv.vck@vimaru.edu.vn

In this numerical study, physical characteristics of cavitating flow around a two-dimensional hydrofoil was investigated using a Large Eddy Simulation (LES) framework. To capture the phase change, the Schnerr–Sauer cavitation model was applied to the simulation. First, the numerical results were carefully validated with current experimental study to ensure the accuracy of the numerical scheme. Then, systematic analysis of cavity evolution around the hydrofoil, velocity fields and streamline behaviors, and pressure distribution on the surface of the hydrofoil under two different flow conditions (σ = 2.57 and 4.95) were carried out. The results indicated that cavitation numbers have significant effects on the formation of the cavity as well as stability of the cavity dynamics. In particular, at high cavitation number, no cavity was observed on the suction side of the hydrofoil. However, as the cavitation number decreases to 2.57, the local pressure dropped significantly, leading to cavity formation. In addition, the acoustic analysis showed that cavitation substantially increased the sound pressure level (SPL) over a wide range of the frequencies. Moreover, formation of cavities on the suction side of the hydrofoil significantly induced instability of the hydrodynamic forces. Findings from this numerical study demonstrate unexpected influences of the cavitating flow on the hydrofoil. This provides valuable insight into the design and optimization of the hydrofoil geometry to reduce cavitation effects.

2026-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/54 2026-04-07T00:45:49+07:00 Assoc. Phd Van Diem Le diemlv.mtb@vimaru.edu.vn Dr. Van Tung Dam tungdv.mtb@vimaru.edu.vn

In many inland waterway tourism destinations in Vietnam, passenger transportation still relies on traditional rowing boats or small motorized vessels, whose operational efficiency and environmental performance remain limited. This study presents a CFD-based investigation of the hydrodynamic resistance characteristics of a representative small passenger vessel intended for inland tourism under calm-water conditions. The hull model was developed from surveyed vessel types currently operating in Vietnamese inland tourism areas, and its performance was evaluated over a practical service-speed range of 2.0–4.0 m/s, corresponding to the displacement, transition, and lower semi-planing regimes. The numerical simulations employed a two-phase air–water model together with a dynamic fluid–body interaction approach to capture free-surface flow and vessel motions. The results show that total resistance increases from approximately 160 N at 2.0 m/s to 578 N at 4.0 m/s, while the resistance coefficients indicate that the residual component remains dominant and the influence of pressure-related and wave-making effects becomes increasingly significant with speed. Additional analysis of wave patterns and hull-surface pressure distribution provides physical insight into the hydrodynamic mechanisms governing the resistance behavior. The obtained results contribute to establishing a baseline hydrodynamic reference for representative inland passenger vessels and provide a practical basis for preliminary propulsion-power estimation and initial electric-propulsion selection for sustainable inland tourism applications.

2026-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/53 2026-03-18T13:12:23+07:00 Dr. Thi Duong Pham duongpt.vmt@vimaru.edu.vn Dr. Huu Long Tran Dr. Thi Thuy Hang Dinh

The plastics manufacturing industry in Vietnam has expanded rapidly, reaching nearly 11.13 million tons by 2025, leading to the widespread use of additives such as phthalates, bisphenols, flame retardants, heavy metal stabilizers, etc. Although these substances improve the properties of plastic products, they pose serious risks to the environment and human health. This study surveys the current status of plastic additive use in Vietnam, classifies the main types of additives, examines their emission mechanisms into the environment through production, use, and disposal stages, and assesses their impacts on air, soil, water, and human health. The results show that plastic additives can be emitted through industrial emissions, waste incineration emissions, leachate, microplastics, and indoor dust; leading to environmental pollution, bioaccumulation, and human exposure through inhalation, ingestion, and skin contact. The study also proposes several management solutions, alternative technologies, and policies, such as applying green chemistry, regulating the concentrations of toxic substances, ensuring transparency in the chemical composition of plastic products, and improving the collection and recycling of plastic waste. These measures aim to minimize the use of toxic additives, thereby limiting negative impacts on the environment and public health.

2026-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/39 2026-01-27T20:55:17+07:00 Dr. Khac Tiep Do dotiep84@gmail.com Dr. Van Tien Nguyen nguyenvantien@vimaru.edu.vn

This paper addresses the challenge of robust heading control for Autonomous Underwater Vehicles (AUVs) operating under variable speed conditions, subject to system nonlinearities, parametric uncertainties, and actuator constraints. We propose a hierarchical control architecture that integrates Sliding Mode Control (SMC) with an optimization-based Control Allocation (CA) scheme. The outer-loop SMC guarantees robustness by computing the required total yaw moment to reject disturbances and track the reference heading. The inner-loop CA then optimally distributes this virtual control effort to individual actuators, explicitly accounting for saturation limits and speed-dependent actuator effectiveness. The performance of the proposed SMC-CA strategy is validated through comprehensive numerical simulations. Results indicate that the system maintains high tracking accuracy and stability across a wide speed range, demonstrating significantly faster transient response and superior disturbance rejection compared to a conventional PID controller in various scenarios, including step changes and abrupt speed variations.

2026-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/47 2026-03-19T02:10:00+07:00 MSc Trung Kien Pham Manh Hung Le hunglm.kt@vimaru.edu.vn BSc Trung Quan Dao

In the context of global climate change and increasing environmental pollution, the development of green transportation has become a key objective towards sustainable development. Within this landscape, Generation Z emerges as a population group with a strong influence on consumer trends and shaping social behavior. However, Gen Z's choice of green transportation services is still influenced by such various factors as cost, convenience, infrastructure, technology, and brand image. The study aims to evaluate the priority levels of criteria for selecting green transportation services within practical significance, helping transportation businesses and policymakers build more effective strategies in the process of green growth. This study applies the Fuzzy Analytical Hierarchy Process (FAHP) method in R software along with a survey scope of 49 Gen Z students studying at the Vietnam Maritime University in Haiphong. The results show that the three most important factors are travel time, quality, and reliability, while the other least perceived ones are service cost, social norm, and green brand. It contributes empirical materials to Gen Z’s green consumption behavior in the local context as theoretical meanings. Also, practical meanings go to some recommendations for companies and policymakers to build core strategies to attract more customers as well as follow the green growth.

2026-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/10 2026-05-26T09:49:23+07:00 PhD. Student Hyun Jin Kang pmths30@naver.com Phan Van Hung phanvanhung@vimaru.edu.vn

E-Navigation is considered a fundamental solution for digital transformation in the Vietnamese maritime industry. In this paper, the authors propose a practical framework for assessing Vietnam's current readiness for e-Navigation. The main factors for assessment include: Governance and Standardization, Technology Infrastructure, People and Processes, and Information and Data. Furthermore, these four main factors are assessed in detail according to thirteen factors that have been refined based on international guidelines and expert analysis and evaluation. Since expert analysis and evaluation may be uncertain, to determine the relative weights of the factors, the Fuzzy Analytical Hierarchy Process (Fuzzy-AHP) was applied. The results show that the main factor of Governance and Standardization has the highest weight. This is followed by the factors of Technology Infrastructure and People, respectively. The results of this assessment indicate the hierarchical harmonization of the criteria which will be an important basis for maritime state management agencies and related organizations in developing e-Navigation development plans in Vietnam. In the future, this assessment method can be referenced and adjusted to develop e-Navigation for countries with similar conditions.

2025-06-30T00:00:00+07:00 Copyright (c) 2026 International Journal of Marine Science and Technology