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k_buz April 6, 2009 04:25

FSI Simulation unsing ANSYS Multifield
Hello everyone

At the moment I'm busy doing my bachelor thesis. I'm trying to simulate a Fluid-Solid-Interaction of a helicopter blade.
As I am new to CFD I am probably not 100% aware of what im doing :D

I have the following setup:

The outer domain is a static domain which velocity is 0. inside is a dynamic domain which spins with 3000rev/min. in the smallest domain is the blade. The highlighted area is the fsi interface.

The goal would be to see the equilibrium position of the blade.
I have first tried to simulate it as a static structural problem. so the inputfile was set to be so. when i simulated it in cfx the blade wouldnt deform at all.
so i also tried to use a transient simulation using a dynamic simulation within the input file. but then this happend (it only calculated about 15mins, then an error came)

It looks as if the forces were much to high.

I am not sure about my settings at all: When using transient setup, the initial conditions must be set. for the rotating domain, I used 0m/s initial speed, but the domain motion under general settings I set to 3000rev/min. would that produce a step, which destroys the blade? or why did that happen?

actually I am not interested in the transient behaviour.. I'm only interested in the final position of the blade. Wouldn that be possible with a static structural simulation??

Please tell me if you need further information to help me :)

Thanks for your help..

michael_owen April 6, 2009 16:55

Have you run a steady state CFX model to get a better initial condition? The initial forces on the blade will be very high unless you do this.

k_buz April 6, 2009 17:40

Could you explain what exactly you mean? I have tried to simulate it as a steady state and as a transient model. How do you mean "to get a better initial condition"?

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