same wind tunnel size for two different models

[MWMonteith]

Hello,

I am a current student and I am new to Autodesk flow design.  I am doing some work for a team of designers at my school, they are trying to compare drag forces on a go kart with a fairing on it to and a go kart without a faring.  When I upload the models into flow design, the wind tunnel sizes are different because the assembly files are different, and the drag forces displayed make the fairing seem arbitrary.  I know you can change wind tunnel sizes with by dragging the arrows, but is there anyway to ensure that the sizes are the same?

Thanks,

Thomas 

[Royce_adsk]

If I understand correctly, you are looking to be able to type in the size of the wind tunnel directly?

Cheers,

[mayur_dhumal]

Hi Thomas,

For every model, Flow Design determines a default size for the wind tunnel based on the size of the model.
For best results, the gap between the wind tunnel and the model should be two to three times the dimension of the model in that respective dimension.
The wind tunnel should also be adequately sized in the direction of flow. Ideally, the wind tunnel should extend at least 2 model lengths upstream and at least 4 model lengths downstream. This distance ensures that the boundaries do not artificially affect the flow approaching the model, and allows correct formation of the wake downstream of the model.

For more info refer : http://help.autodesk.com/view/ADSKFD/ENU/?guid=GUID-9B85F4A0-5072-454D-8710-CCFF26507BE9

Regards,
Mayur

[Radon_Autodesk]

Hello, I have the same question, it has not been answered yet, what Thomas needs is to be able to run two or more models under the exact tunnel dimmensions, this is really hard to achieve if not impossible as even when you drag the arrows to the desirable tunnel dimensions, later on the program will re-dimension the tunnel after calculating the mesh. The question again, is if there is a way of fixing the tunnel dimensions to a certain value so one can produce comparable results

[Royce_adsk · Accepted solution]

I would suggest adding this to the idea station (http://forums.autodesk.com/t5/flow-design-ideastation/idb-p/idea10)

The basic suggestion would be to add wind tunnel sizes based on where the anchors are in the 'Wind Tunnel Settings' window.  I could make the suggestions, but you adding it provides more weight to getting it done!