Physics-Based Simulation of Ocean Scenes in Marine Simulator Visual System

Haijiang Li,Shaoyang Qiu,Hongxiang Ren,Chang Wang

doi:10.3390/w12010215

Abstract

The realistic simulation of ocean scenes is of great significance in many scientific fields. We propose an improved Smoothed Particle Hydrodynamics (SPH) framework to simulate the ocean scenes. The improved SPH combines nonlinear constant density constraints and divergence-free velocity field constraint. Density constraints adjust the particle distribution on position layer, so that the density is constrained to a constant state. The addition of the divergence-free velocity field constraint significantly accelerates the convergence of constant density constraint and further reduces the density change. The simulation results show that the improved SPH has high solution efficiency, large time steps, and strong stability. Then, we introduce a unified boundary handling model to simulate coupling scenes. The model samples the boundary geometry as particles by means of single layer nonuniform sampling. The contribution of the boundary particles is taken into account when the physical quantities of fluid particles are computed. The unified model can handle various types of complex geometry adaptively. When rendering the ocean, we propose an improved anisotropic screen space fluid method, which alleviates the discontinuity problem near the boundary and maintains the anisotropy of particles. The research provides a theoretical reference for the highly believable maritime scene simulation in marine simulators.

Highlights

Marine simulator has been widely applied to fields of marine education and training, engineering demonstration, scientific research, etc
In our novel Smoothed Particle Hydrodynamics (SPH) method, we propose a density constraint solver based on nonlinear constant density constraints, and try to replace the constant density solver in divergence-free SPH (DFSPH) method with a novel density constraint solver
The physical model was implemented using C++, the rendering part was based on modern OpenGL, and the integrated development environment was Microsoft Visual Studio 2019

Summary

Introduction

Marine simulator has been widely applied to fields of marine education and training, engineering demonstration, scientific research, etc. The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers and its amendments put forward a series of mandatory requirements and suggestions on the performance standards, scope of application, and rules of use of marine simulators. Improving the performance of marine simulator is required by both international conventions and navigation practice. Ocean waves account for about half of the whole visual system in the marine simulator. The fidelity of the ocean scene directly affects the immersion of the whole marine simulator. The ocean waves are an important object in the study of ship seakeeping property and maneuverability, and accurate ocean wave model can improve the fidelity of simulator manipulation. There are many modeling methods for ocean waves in computer graphics, and the most commonly used ones are the spectrum-based approaches and computational fluid dynamics (CFD) methods

Methods

Results

Conclusion