Learning Forum

[toni1398]

I am running some cfd test to a motorbike in fluent 19.0 and I dont know why the cd values are so high (in the order of 10^7)

[aitor.amatriain]

Could you please give us more information? Contours of the mesh and velocity, pressure, BCs, reference values for Cd...

[Rob]

Especially the latter - everyone misses that.

[toni1398]

bc: velocity inlet, pressure outlet, ground and sky moving walls, symmetry

[Rob]

Have a look in the various NACA aerofoil examples (there's probably on in the Help system in the newer releases). You need to alter the reference values to suit the model.

[toni1398]

moreover when I try to add rotationary movement to the wheels this happens: too high speeds in one of them. do you know what i could fix?

[Rob]

Assuming you set the centre of rotation and axis correctly check the spacing and mesh resolution between the tyre and mud guard.