Sea Robot Motion Immersed in Water: Dynamic Mesh

Sea Robot Motion Immersed in Water (Dynamic Mesh) — ANSYS Fluent CFD Simulation

Description

This project presents a CFD simulation of a sea robot moving through water using the Dynamic Mesh technique — the essential method for problems where a body physically moves through the fluid domain and the computational cells must change shape and position over time. In this project, the robot (modeled as a cube) starts on one side of the domain and travels toward the inlet against an oncoming water stream, letting you study the pressure buildup ahead of it and the wake region trailing behind. Within the Marine Engineering: Beginner CFD Training Package, this project introduces dynamic mesh for a body in motion, marking the step from fixed-geometry and free-surface cases toward genuine moving-body simulation.

Methodology

The 2D moving-body domain is designed in Design Modeler and meshed in ANSYS Meshing with roughly 30,010 elements. Because the location and shape of the computational cells change as the body moves, a Dynamic Mesh is mandatory, and a transient solver is required. Smoothing and remeshing work together to maintain high-quality elements as the body advances, preventing the mesh degradation that causes solver errors, with the mesh regenerated at a remeshing interval of every 50 iterations. A prescribed velocity profile is imposed on the moving body — 3 m/s in the X-direction over 0–3 seconds — while the surrounding flow is set up with an inlet water velocity of 1.5 m/s using the standard k-ε turbulence model.

Analysis

Post-processing produces velocity, pressure, and turbulent-viscosity contours along with streamlines, revealing the elevated stagnation pressure ahead of the robot and the wake region trailing behind it. From these results you can study how the moving body loads the surrounding water and how its wake develops over time. Dynamic Mesh is the gateway to simulating real motion — submarines, AUVs, valves, pistons, projectiles, and store separation — and mastering smoothing and remeshing here equips you for an entire class of moving-body CFD problems. By the end of this project, you'll be able to set up a transient dynamic-mesh simulation, configure smoothing and remeshing to preserve mesh quality, prescribe the motion of a body through a fluid, and interpret the pressure and wake fields it produces.