Hi, I simulate natural convection in channel,after running i want to calculate velocity of outlet and compare with experimental data, but don't know that i use of area weighted average or mass weighted average.which is better for post processing? Thanks alot
As was mentioned, it depends on your experimental setup. If you determined the experimental velocity value via a volume/mass flow rate sensor, you would now use the mass-weighted averaging. If you measured the velocity at several points over a cross-section, the area-weighted average would be probably better.
@zbynek kalal:thanks alot for your answer.i have experimental data calculte with anemometer that was placed 15 cm inside the exit of channel.do you think that this is volume or mass glow rate sensor?
Dera abdul. I try to valid my simulataion with experimental paper and in paper dont describe more about it. Seyede sahar
Dear abdul,its name is hot wire anemometer having an accurcy of 0.01 m/s.(the anemometre was placed 15 cm inside the exit of flow channel,at the center of the cross section.it has been assumed that the mean stream velocity,together with the cross sectional area and discharge cofficient gives net volume flow through the channel).
Dear seyede sahar Hosseini,
Which of area weighted average or mass weighted average is better can be judged while formulating the problem and interests of analytical point.
I think that Abdul pretty much answered. If the velocity was measured at a single point, then there is not a reason to average your results. If the velocity was measured at several points, then you could use area-averaging over the area that is covered with these measuring points.
As for the anemometers - there are various types, 1-D, 2-D or 3-D, so you need to find out which one was used in the experiment and whether the quoted velocities are total velocity magnitudes or single component magnitudes.
If there is no return flow, use bulk velocity and bulk temperature (definitions are available in a lot of books).
As an addition to my first reply, please see my last paper "Mixed thermal convection", Anais da Academia Brasileira de Ciencias, 2015.
Regards
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