International Journal of

---

As the first phase of a series of monitoring and modeling studies of Iranian coastal areas, Chabahar Bay, located on the north coast of the Gulf of Oman, was under a comprehensive monitoring and modeling study in 2006-2007. The study included an extensive one-year field measurements program to help understanding the ongoing processes in the bay and provide inputs or boundary conditions and validation data for numerical models. An analysis of the collected data and the results of three-dimensional (3D) hydrodynamic numerical modeling are described in this paper. 3D numerical model of MISED was employed to provide a full spatial picture of bay-wide circulations and its sensitivity to environmental factors such as tides and winds. MISED simulations were completed for the months of February and March 2007 and the results were compared with the measurements. It was observed that the simulated tidal currents favorably agree with the measured data at the selected stations. Particle tracking simulations using a Lagrangian Particle Tracking Model showed that the combination of wind-driven and tidal currents generates a self-flushing function that tends to carry suspended material to outside of the bay. The combination of winds and tides has thus a very important assimilative function for water quality of Chabahar Bay.

---

Breaking waves have ability to transport large quantities of sediment and significant impact on coastal structures morphology. Hence, modeling of wave breaking is an important subject in coastal and marine engineering. In this research, the periodic wave breaking process on a plane slope is studied experimentally and numerically. Laboratory experiments were conducted to record water surface elevation and the wave breaking process. For the current study, a space-averaged Navier–Stokes approach together with laboratory experiments has been deployed to investigate time-dependent wave breaking processes. The developed model is based on the Smoothed Particle Hydrodynamic (SPH) method; a pure Lagrangian approach; capable of handling large deformations at free surface with high accuracy. So, a Weakly Compressible version of the Smoothed Particle Hydrodynamics (WCSPH) method together with a large eddy simulation (LES) approach was used to simulate the wave breaking on a plane slope. The results of numerical simulations were compared both qualitative and quantitative with those of laboratory experiments. Overall, good agreement was found between them. Finally, it is shown that the WCSPH method provides a useful tool to investigate surf zone dynamics.

---

Planing vessels usually have low ratios of resistance to weight, so they can move fast on sea surface than the displacement or semi-displacement ships. Access to higher speeds is one of the attractions for designers and users. To achieve higher speeds, reducing the hydrodynamic resistance is a necessity for this class of vessels. In this study, a 3D finite volume approach is used to analyze the hydrodynamics of the Cougar high-speed vessel, a hard chine planing hull. In addition to use of the URANS equations for momentum, SIMPLE algorithm for coupling of the pressure and velocity field and the k-e for turbulence modeling, the fluid phases of air/water and the free surface are modeled using the volume of fraction (VOF) scheme. Moreover, in the simulations, instead fixing the freedom of the model regards to the computational domain, the vessel motions are also considered to have two degrees of freedom, 2-DOF, using the newly developed moving mesh technique of Overset. The grid independency study shows a good consistency between the numerical results and experiments for the vessel resistance, trim angles and the heave. Main emphasis of this paper is on study of the effects of different loading conditions, the vessel weight and the longitudinal center of gravity, on the hydrodynamic characteristics such as resistance, trim angle and the vessel sinkage. All of the numerical simulations are done using the commercial software of Star CCM+

---

High-speed monohull vessels with chine hulls are widely used due to their simple design, but maintaining optimal performance at high speeds requires precise hull force analysis. This study utilizes 3D scanning to capture hull geometry, refining it in AutoCAD for efficiency. Hydrostatic and hydrodynamic assessments are conducted using Maxsurf, applying the Switkowski method.
The study examines vessel motion, crew comfort, and water ingress under different sea conditions. Results indicate that at a 5.4-degree trim, pitch motion intensifies in harmonic waves, yaw motion increases in beam waves, and pitch and heave motions are more pronounced in head waves. Water ingress becomes a concern at this trim in Beaufort 2 and 3, with MSI peaking at 12.5% in Beaufort 3. The lowest resistance occurs at 5.22 knots, but higher trims raise power demands. Manual trim adjustments using outboard engines and jacks effectively mitigate these effects.