estimating turbulence intensity
 

hi. does anyone know how I can estimate the turbulence intensity in a channel flow with only turbulence in the boundary layers? i know of I = 0.16 * (Re_dh)^(-1/8), but this is only valid for fully developed pipe flows. I will use this to obtain an estimate for the modified viscosity used in the spalart-allmaras model with the boundary layer thickness being the relevant dimension of the problem.

thank you very much!


regards,

Ken-Robert G. Jakobsen

Reynolds number based on momentum thickness
 

you could try calculating a Re number based on momentum thickness. so there is a general rule stating this thickness is (7/72)*full boundary layer thickness. Re mom would then use this as the characteristic length scale. consider what kind of resolution you are looking for as well.

'Convective Heat and Mass Transfer' by Kays (2004) might be a good reference as well.