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Question on the weak expression

Posted Jul 11, 2011, 1:43 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Modeling Tools & Definitions, Parameters, Variables, & Functions 0 Replies

Pooyan Tirandazi
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Hello,

I'm trying to understand how the weak term works by looking at the equation in each nodes..

For example, I opened the stationary "Laminar Flow" physics and then looked at the equations under the "Fluid Properties 1". What I see in the "weak expression" box are three terms:
1) pressure + shear stress
2) body force + convective terms
3) continuity ?

Here my question is:
a) equations 1) and 2) seem to be pieces of the Navier stokes equation. How does COMSOL correlate the two separate terms into a single Navier-Stokes equation?
b) why is the test function using "p" instead of "ux" or "vy" in the continuity equation. I had the ? behind 3) because of this... rho(ux+vy) definitely seems like the continuity equation but why the "p" term? What is it testing?

Any comments on this would be a lot of help.

Thanks!

Best,
TJ
0 Replies Last Post Jul 11, 2011, 1:43 p.m. EDT
COMSOL Moderator

Hello Pooyan Tirandazi

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