Experimental work to prove that the Drag Coefficient of a sphere is 0.5

[daniscp]

Is there any experiments I could do to prove that the Drag Coefficient of a Sphere is more or less 0.5 depending on the roughness of the sphere?

 

[Mech_Engineer]

The obvious question- do you have access to a wind tunnel?

Other than that, it might be possible to levitate the sphere in a vertical tube with air blowing through at its terminal velocity, or perhaps drop the sphere a long distance and measure its fall time very precisely, and compare that time to a calculated fall times with and without drag?

 

[Mech_Engineer]

I recognize your name now... Isn't this basically a repost of your previous thread?

 

[daniscp]

The obvious question- do you have access to a wind tunnel?

Other than that, it might be possible to levitate the sphere in a vertical tube with air blowing through at its terminal velocity, or perhaps drop the sphere a long distance and measure its fall time very precisely, and compare that time to a calculated fall times with and without drag?

Yeah I have access to a wind tunnel...

It's not a repost since I've decided now to focus on proving that the drag coefficient of a sphere is 0.5. The only thing I need to think of is an experiment to measure the drag force...but can't come up with one

 

[brewnog]

How about some strain gauges?

 

[jaap de vries]

You can measure the flow velocity behind the ball using a pitot at several locations that you can calculate the momentum change which is equal to the drag force so you divide that by D*rho*V^2*0.5 and you will probably get a value near 0.5 (plus or minus 0.5).