Same conditions but different reynolds number
 

Hi!

I'm trying to study CD for airship envelope shapes depending on different paramenters: length/diameter, volume,etc.

I have data for different reynolds numbers o check my results, but I have to carry out the simulations without changing the velocity magnitude, density and viscosity. How can I do that?

What length I have to set as characteristic length to get the Reynolds number: The envelope length or the sphere diameter where I put inside the envelope for the simulations?

Thanks!

Luis