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-   -   Advise with a wheel simulation (http://www.cfd-online.com/Forums/fluent/38688-advise-wheel-simulation.html)

Freeman November 21, 2005 11:05

Advise with a wheel simulation
 
Hi all (again)!

Which is the best way to simulate the folw over a car wheel (in 3D)?

I know some issues with the contact wheel and ground: it cannot be tangent, there must be a "contact patch". But if there is this contact patch, the simmetry does no longer exist, so I can't rotate the wheel mesh... what can I do? I only have an idea, and it is about to say Fluent that the tire and the rim "walls" have a velocity (a rotation).

And what about with the "roughness" of the tire?

Alan November 21, 2005 16:15

Re: Advise with a wheel simulation
 
Hi Freeman,

Hope this helps, you dont have to use a moving mesh. Just define your 3D wing as a wall, and in boundary conditions define it as a spinning wheel. Yes, make sure you get the angular velocity right which you calculate from a formula based on your wheel radius and linear velocity.

The only problem you might have is to get a converged solution. The damn thing hardly converges!

Hope this helps and good luck!

Alan.

Freeman November 21, 2005 17:25

Re: Advise with a wheel simulation
 
Thaks for your answers, Alan!

OK, there's only one more question. How can I represent the roughness of the wheel in a realistic way? What roughness value did you use in your simulations? As far as I can remember, I think that there are some turbulence models in Fluent that the roughness is disabled (RSM and other one I think): in these cases, is there any possibility to simulate tire's roughness?

Many thanks!

Alan November 22, 2005 05:42

Re: Advise with a wheel simulation
 
Hi Alan,

To be honest, I wouldnt worry about the tire roughness at this stage since it can cause even more turbulence and there is no such turbulence model that can handle that. Use the default values, get some initial values and try playing with different roughness values of your choice.

Depends how much accuracy are you after!

Thanks,

Alan.

Freeman November 22, 2005 11:00

Re: Advise with a wheel simulation
 
OK! Thanks for all Alan. Bye!


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