Hello,

I am trying to model a porous zone using the experimental data in FLUENT solver, and stuck with a simple yet difficult issue. I am referring to the FLUENT manual, which has shown an example of a test case for a pressure drop against velocity (see attachment). Using a trend-line, an equation was deduced that is without the constant term; del_p = 0.28296v^2 - 4.33539v.

I tried using the same inputs, but end up in a different 2nd order polynomial expression for the trend-line that includes the constant term, and the equation changes as well; del_p = 0.3119v^2 - 8.5428v + 126.63. Any tips on altering the linear regression approach.

Could someone please shed some knowledge?