HI,my project involves porous media flow. i have the value of pressure drop across the length of the porous medium.and the velocity of fluid at entry to the pipe is also known.the porous medium is quite a distance away from the entry.i need to know how the values of alpha(a) and beta(b) can be calculated from the expression dp/L=(a*v^2+b*v).what velocity should i substitute in this relation.the STAR-CD methodology says its the characteristic velocity.how do i get that.kindly help.thanks all!!! and the flow is orthotropic

You can use the average velocity across a section of your porous region. to calculate alpha and beta you need two data pairs of pressure drop as a fct. of velocity.

thanx Mork i'll plug in the average velocity as u suggested.can u please elaborate on what u meant by saying "two data pairs of pr.drop as a factor of velocity".

You got an equation with two variables. You know the pressure drop for one flow rate value (and therefore for one velocity). If you know the pressure drop for a second velocity value, you can determine alpha and beta without problem. Hope that helps!

yes i got that!!thanks.Regards!!