Cd of a truck in a wind tunnel
 

Hi guys,

First of all thank you.

I am studying the Cd of a truck in a wind tunnel (Ignoring the effect of the wheels).

BC:
1. speed of 80 km / h
2. Grid adaption to the y + (50 <y+ <500)
3. Moving Ground (case in relative motion format)

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GAMBIT & FLUENT


1. I subtracted the geometry of the truck, to get a single volume (this procedure is correct?)

2.I entire volume meshing (Scheme Elements: Tet / Hybrid, Type: TGrid, Spacing: 30 (interval count), Total elements: 339862)

My question :

1. Need to create a finer mesh underneath the truck? if so, can I do in Gambit? (I've tried different ways but I failed meshing this area).

2. How do I know which is more correct meshing for these situations and what should be the number of elements to this mesh?

3. I have to create a BL in all walls of the truck? or with the option to "use grid adaption to the y + variable" is enough?

4. How would the distribution grid?


Thanks again,