# Simulation Water Wheel Fluid Structure Interaction (FSI)

Figure 1: CAD model created in NOGRID's COMPASS

Figure 2: Setup the water wheel case within the GUI

Figure 3: Water wheel fluid velocity at a certain time step

Figure 4: Animation of the water wheel in full 3D

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

## Nogrid's strengths

Particular strengths of NOGRID's fluid flow CFD software are the rapid preprocessing (no fluid grid needs to be generated, only the boundary mesh, inner finite points are generated automatically depending on User setting initially and during computation), and the outstandingly short computation time even for complicated cavities.
As you can see in the image below, the boundary of the geometry still requires a mesh to allow the interior finite points to detect the boundary. The boundary must therefore be meshed and the finite points inside are automatically generated during the simulation controlled by User specifications.

## What is CFD from NOGRID?

CFD solves the fundamental equations that define the fluid flow process. With CFD software from NOGRID every engineer makes better decisions by predicting, analyzing and controlling fluid flow, heat and mass transfer or chemical reaction. By using NOGRID software for flow modeling you receive information on essential flow characteristics as for example flow distribution. Using it additional to testing and experimentation NOGRID software helps to improve the evaluation of your design – resulting in better construction and operation parameters, increasing planning security and money savings due to faster time to the marketplace for your product or process.

## Choose NOGRID

With NOGRID, you choose professional CFD software and services – our aim is helping you to be successful. When you decide to work with NOGRID you choose close cooperation with a dynamic, flat hierarchies-organization. Short information channels result in quick and accurate professional support and service. Our team consists of highly qualified employees, who are experts in fields such as numerical simulation or computational fluid dynamics. Based on our know-how, we are pleased to offer the following services, responding to your individual requirements:

## TRAINING

In our two-days training courses you will learn, how to use NOGRID CFD software efficiently. Our technical support team will teach you how to handle and solve different cases.

For more details please refer to Training Courses →

## Technical Support

We offer full professional support from the minute you start using our software, by telephone or by email. Contact us, when ever needed.

For more details please refer to Software Support

## Service

Lack of time or resources and other constraints often make outsourcing an attractive solution. We help you with your flow modeling needs. Based on our engineering expertise in this field we offer individual numerical simulation services matching the unique needs of your organization.

For more details please refer to Simulation Services →

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