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Roued December 22, 2000 05:22

Blockage in CFD code
 
Hi,

I am currently playing with the CFD code in that comes with the book by Peric and Ferziger.

I would very much like to implement a method for setting blockage internally in the domain.

Can any one give me a hint on how to do this ?

What is the best way ?

Thanks in advance.

Regards

Roued

Abhijit Tilak December 23, 2000 04:31

Re: Blockage in CFD code
 
hi Roued,

I am not sure how the code u are referring to is written. but the general way is (Patankar's funda). for any grid point u write the equation as

Ap_phi_p = Sigma A_i Phi_i +Su

Where Ap= Sigma A_i+Sp

Phi is a general variable (u,v,w,t,p,k,e ....)

Make Sp very large (say 1e25) and similarly Su= 1e25 (must be equal to value of Sp) for the grid point for which u want to freeze the value. U can initialise the value required and it will remain unchanged throuthout the iterations. if u put Phi_p =0 for u,v,w u will create islands in the flow path. Specify these values for all the grid-points that u want to freeze.

Note: for equations having large value of variables this may blow up due to overflow (typically k-e) Some care is required in grid spacing at blocked areas.

Hope this helps

Abhijit Tilak.


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