Is there any possibility to compute boundary layer parameters (delta_1, delta_2, H_12) in Fluent ?

Dirk

Hi,

This is the way I understood your Q. You are modeling a flow over a solid surface (internal/external) and wanted to compute the boundary layer (am assuming turbulent flow here - laminar shouldn't be an issue), displacement and momentum thicknesses. Fluent DOES NOT have a ready made function to extract these values (i think disagreement on the defn of Boundary Layer thickness being one ) - if this is your question. But you can write a UDF or just use any postprocessing tool...( I remember using excel for example some years back ). Extract the velocity component/s first at a specific location along the flow direction and then ur definition of BL. If it is external flow, you will have to extract it at multiple points along the flow since the B.L is continuously increasing. I wrote a UDF sometime ago to do just that but I couldn't find it right now. But you can get some information directly from Fluent...parameters like wall shear, y+...... etc and then use these values.

regards

Melaku Habte

Hello,

it is no problem for me to compute displacement and momentum thickness with Matlab after I exported the velocity data. But I plan to do some computations with transition models where the beginning of transition is determined by a certain momentum thickness or shape parameter, so I should find a way to compute these values within Fluent during the calculation. I know this will have to be done with a UDF, but unfortunately I have no idea how. So I will be thankful for any ideas.

Dirk