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Claudia January 30, 2007 13:20

Directional loss model

I would like to simulate a porous plate inside a duct. I know all dimensions. The plate is 51% open. I would like to use the Directional Loss Model. I'm not really sure what CFX want to know in this model. Is the "permeability" the part of the plate which is open (open area)? And what is the "Resistance Loss Coefficient"? I only know the zeta value for the plate. I know that it isn't the same.

Thanks for help


Robin January 30, 2007 13:54

Re: Directional loss model
Hi Claudia,

This is covered in the documentation.


Claudia January 31, 2007 14:07

Re: Directional loss model
Hi Robin,

I know that there is something written in the documentation, but not for the questions I have. Maybe I have some problems to understand. So I need help to understand what kind of value I should write at "permeability" and "resistance loss coefficent".


Reza Farahani February 8, 2007 21:15

Re: Directional loss model
Hi Claudia,

Permeability depends on the type of porous medium that you have. The directional loss is the loss associated with the porous medium which is included in the general momentum equation as a source term. If you read ANSYS CFX-Solver, release 10.0: Theory Page 66, you will understand how CFX calculates the loss coefficients. But in your case, based on the viscosity of the material you have chosen and the permeability, you wont need to assign any value to the coefficients unless you want them to be specific values.

hope this helped, Reza

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