ANSYS原版流固耦合计算实例

Oscillating Plate with Two-Way Fluid-Structure Interaction

ANSYS-China

Introduction This tutorial includes:

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Features

Overview of the Problem to Solve

Setting up the Solid Physics in Simulation (ANSYS Workbench)

Setting up the Fluid Physics and ANSYS Multi-field Settings in ANSYS CFX-Pre Obtaining a Solution using ANSYS CFX-Solver Manager Viewing Results in ANSYS CFX-Post

If this is the first tutorial you are working with, it is important to review the following topics before beginning:

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Setting the Working Directory Changing the Display Colors

Unless you plan on running a session file, you should copy the sample files used in this tutorial from the installation folder for your software (/examples/) to your working directory. This prevents you from overwriting source files provided with your installation. If you plan to use a session file, please refer to Playing a Session File. Sample files referenced by this tutorial include:

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OscillatingPlate.pre OscillatingPlate.agdb OscillatingPlate.gtm OscillatingPlate.inp

1. Features

This tutorial addresses the following features of ANSYS CFX.

Component Feature User Mode ANSYS CFX-Pre Simulation Type ANSYS Multi-field General Mode Transient Details Component Feature Fluid Type Domain Type Turbulence Model Heat Transfer Output Control General Fluid Single Domain Laminar None Monitor Points Details Transient Results File Wall: Mesh Motion = ANSYS MultiField Boundary Details Wall: No Slip Wall: Adiabatic Timestep Transient Animation ANSYS CFX-Post Plots Contour Vector In this tutorial you will learn about:

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Moving mesh

Fluid-solid interaction (including modeling solid deformation using ANSYS) Running an ANSYS Multi-field (MFX) simulation Post-processing two results files simultaneously.

2. Overview of the Problem to Solve

This tutorial uses a simple oscillating plate example to demonstrate how to set up and run a simulation involving two-way Fluid-Structure Interaction, where the fluid physics is solved in ANSYS CFX and the solid physics is solved in the FEA package ANSYS. Coupling between the two solvers is required throughout the solution to model the interaction between fluid and solid as time progresses, and the framework for the coupling is provided by the ANSYS Multi-field solver, using the MFX setup.

The geometry consists of a 2D closed cavity. A thin plate is anchored to the bottom of the cavity as shown below:

An initial pressure of 100 Pa is applied to one side of the thin plate for 0.5 seconds in order to distort it. Once this pressure is released, the plate oscillates backwards and forwards as it attempts to regain its equilibrium (vertical) position. The surrounding fluid damps the oscillations, which therefore have an amplitude that decreases in time. The CFX Solver calculates how the fluid responds to the motion of the plate, and the ANSYS Solver calculates how the plate deforms as a result of both the initial applied pressure and the pressure resulting from the presence of the fluid. Coupling between the two solvers is required since the solid deformation affects the fluid solution, and the fluid solution affects the solid deformation.

The tutorial describes the setup and execution of the calculation including the setup of the solid physics in Simulation (within ANSYS Workbench) and the setup of the fluid physics and ANSYS Multi-field settings in ANSYS CFX-Pre. If you do not have ANSYS Workbench, then you can use the provided ANSYS input file to avoid the need for Simulation. 3. Setting up the Solid Physics in Simulation (ANSYS Workbench)

This section describes the step-by-step definition of the solid physics in Simulation within ANSYS Workbench that will result in the creation of an ANSYS input file OscillatingPlate.inp. If you prefer, you can instead use the provided OscillatingPlate.inp file and continue from Setting up the Fluid Physics and ANSYS Multi-field Settings in ANSYS CFX-Pre. Creating a New Simulation

1. If required, launch ANSYS Workbench.

2. Click Empty Project. The Project page appears displaying an unsaved project. 3. Select File > Save or click Save button.

4. If required, set the path location to a different folder. The default location is your working

directory. However, if you have a specific folder that you want to use to store files created during this tutorial, change the path. 5. Under File name, type OscillatingPlate.

6. Click Save.

7. Under Link to Geometry File on the left hand task bar click Browse. Select the provided

file OscillatingPlate.agdb and click Open.

8. Make sure that OscillatingPlate.agdb is highlighted and click New simulation from the

left-hand taskbar.

Creating the Solid Material

1. When Simulation opens, expand Geometry in the project tree at the left hand side of the

Simulation window.

2. Select Solid, and in the Details view below, select Material.

3. Use the arrow that appears next to the material name Structural Steel to select New

Material.

4. When the Engineering Data window opens, right-click New Material from the tree view

and rename it to Plate.

5. Enter 2.5e06 for Young's Modulus, 0.35 for Poisson's Ratio and 2550 for Density.

Note that the other properties are not used for this simulation, and that the units for these values are implied by the global units in Simulation.

6. Click the Simulation tab near the top of the Workbench window to return to the

simulation.

Basic Analysis Settings

The ANSYS Multi-field simulation is a transient mechanical analysis, with a timestep of 0.1 s and a time duration of 5 s.

1. Select New Analysis > Flexible Dynamic from the toolbar.