Learning Forum

[Chinmaya Kumar Patra]

I have a rectangular channel with single phase adabatic flow in which i am calculating the transient variation of dynamic pressure (area wehighted avg) and velocity (area wehighted avg) at different locations (0 mm-inlet , 0.5 mm, 1.5 mm, 2.5mm, 3.5 mm and 4.5mm-outlet) along the length of channel as shown in plots below. It can be seen from velocity plot, the oulet velocity is less as compared velocity at inlet but the dynamic pressure trend is opposite, how is it possible? as the dynamic pressure is a function velocity and density (remians constant through the simualtion).
In addtion the velocity trends for diferent locations are not matching with the dynamics pressure trend.

[Rob]

The clue is "area weighted average".  Have a look at the definitions, and then look at mass weighted. 

[Chinmaya Kumar Patra]

But for calculating both the dynamic pressure and velocity i have used area weighted average. So should i try out both these parameters with mass weighted average.

[Rob]

Have a look at the options to see which is most suitable.