Simulation Water Wheel Fluid Structure Interaction (FSI)

The simulation of the Fluid Structure Interaction (FSI) of a water wheel can perfectly be performed with NOGRID points CFD software.

Free surfaces in fluid mechanical systems are a great challenge for numerical simulation methods in themselves. However, many applications additionally exhibit moving structures interacting with the fluid. In most cases a realistic modeling with today's standard software is simply not feasible or would at least require a non-economical amount of time and computational power to solve every-days' simulation problems.

One such example is the simulation of a water wheel accelerated by the fluid which is injected from the nozzle at the top of the domain. A good understanding of this process is mandatory for guiding the design and optimization of the hull of the wheel.

In grid-based methods such simulations are usually more simplified. Instead of allowing the wheels moving freely during acceleration, the shape of the wheels are very often entirely fixed and their position and orientation do not react on the fluid. This technique reduces computation time and numeric imprecision due to remeshing.

In contrast our fluid modeling software NOGRID points, a meshless CFD (Computational Fluid Dynamics) software permits several approaches for modeling the described scenario more realistically. No restrictions on the movability of the wheels are prescribed. In particular all six degrees of freedom, three for the velocity and three for the rotation of the rigid shape, are available. In the approach presented here the water wheel rests in a box initially not filled with water. The water wheel is modeled as a set of faces which can freely move in the fluid. The fluid-structure interaction of the fluid with these faces is further determined by the center of gravity of the wheel, by its mass and by its inertial tensor. Beginning at time t=0 the fluid starts injecting from the top nozzle and shortly later the fluid interacts with the wheel and accelerates the wheel.

NOGRID unites abilities to handle free surface flow and moving parts in the domain and allows the simulation of any conceivable geometry and operation modes such as

• computation is in full 3D solving complete Navier-Stokes-Equations
• easy and intuitive setup of the FSI (Fluid-Structure-Interaction) case
• free definable material properties by equations or curves
• any wheel geometry with small gaps or cutouts
• open or closed domains including moving of additional parts