roughness of thin surface
 

hi,friends I need to difine different roughness on the twos of thin surface,who knows how to? I have referred to this topic, http://www.cfd-online.com/Forum/cfx_....cgi?read=4397 but I can not distinguish the two surfaces,e.g. which one is the inside one or which one is the upper,anyone could help me? thanks.

Re: roughness of thin surface
 

Hi Colins,

To find the direction, define an outlet boundary condition to the surface. The arrows will be on the side which is touching the fluid. You can then switch it back to a wall and apply the appropriate B.C.

-Robin

Re: roughness of thin surface
 

To robin, I have tried following what you suggested,but I cannot apply a inlet/outlet boundary on a subdomain surface,the error reported was "The surface list 'Solid 4.4' contains the following error(s). Solid 4.4 is not an exterior face of a domain." Btw,I am using CFX5.5 -colins

Re: roughness of thin surface
 

first,you can creat a subdomain which include the thinsurface you will defined,then in the condition boundary,you'd creat the thinsurface,and you may define different roughness on the two side of the thinsurface.may you succeed1

Re: roughness of thin surface
 

Upgrade to 5.6.

-Robin

Re: roughness of thin surface
 

To Robin, thank you.I have done it. -colins