[texanidiot25]

Originally Posted by co_driver

Reynolds Number = ( L * v ) / 'nu'

L = Effective length (or diameter of pipe) [m]
v = velocity [m/s]
'nu' = Greek letter 'n' = kinematic viscosity [m^2/s] (~1.6*10^-5 for air @ 20C)

Re is an indicator of effective flow when comparing scale models of real things (3/8 scale, or ?) - 2X speed for something half the size. So, in the modelling programs, a correct Re must be used.

For nearly all objects there is a typical Re number where transition occurs from laminar to turbulent flow. (a Moody diagram [pipe flow] shows this well)

So what are the best numbers?