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batta31 November 5, 2012 05:43

Boundary conditions on a C mesh
Good morning to everyone,
I have a simple question.. I'm simulating a flow over an airfoil with a "C mesh", and I was thinking about this: in such a mesh i believe that the "inlet" is made up of the C itself plus the top and the bottom, while the outlet is only the remaining patch on the right. But now I'm in doubts if I'm doing the right things..

Can anyone help me?

colinB November 5, 2012 07:04

Dear Simone,

the answer to your question depends on whether you have an inclined flow
or a flow parallel to the skeleton line

for the inclined flow:

  • you define the C and the lower straight wall as an inlet and the straight back and upper wall as outlet (if the flow comes from the lower right corner, is the flow coming from above the upper and lower straight wall definitions are inverted)

for a flow parallel to the skeleton line:
  • you define the C as inlet
  • the upper and lower wall as wall with a no slip condition
  • however take care that the distance wall-profile is big enough to avoid blockage
  • and finally the straight back wall as outlet



batta31 November 5, 2012 07:12

Well, my flow is entering the domain from the "C" which is on the left, with the inclined I have to change my boundary conditions because they were wrong! :) It has sense that the flow enter "from the C" right? I don't have to split it right?

Thanks Colin

colinB November 5, 2012 07:34

As you mentioned the second description matches to your case, thats right.

I have to note that I was assuming that the flow is coming from the
right side with the C part on the right side as well,
(sry I used shipbuilding standards on my foils so everything is little bit
so you have to turn around everything I said.


batta31 November 5, 2012 07:38

Ok so..with my "C" on the left, inclined flow, and flow entering from the left I define the "C" and the lower part as inlet right, while the top and the vertical patch on the right form the outlet?

colinB November 6, 2012 06:40

yes that sounds good

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