[Fabio88]

Dear all,

I am studying the external aerodynamic of bluff bodies (e.g. car) in case of cross wind. Software used is Ansys Fluent.

The geometry I used is placed inside a cylinder (its external surface is an interface with the external part of the domain), which I rotate to get the proper angle I need.

In case of zero cross wind I use a very low turbulence intensity (0.02%, in agreement with a wind tunnel test I found). However in the presence of cross wind this value I guess is not correct since the wind will have a certain content of turbulence energy inside, that can affect the flow dynamics.

My approach was to assume a turbulence intensity of the cross wind to 5% for each angle case, and insert as b.c. this value scaled with the resultant speed:

where V is the cross wind speed and U is the velocity of the body.
The result is a turbulence intensity that grow increasing the angle of attack (i.e. it increases with the increase of the cross wind influence on the flow).
I guess this approach a quite simple one but my fear is that it can not be realistic.
I found few papers about cross wind studies but I never found a description of how they set up this b.c.

Do you have any suggestion about the approach I should use or any reference about it.

Thanks for any help you can provide me.

Best regards,

Fabio