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M Lewis May 13, 2000 18:06

PMARC-12 question
I have been playing around with a copy of pmarc-12 I bought from COSMIC some time ago. I have never fully figured it out yet. The manual assumed that you were already familar with pmarc and was not very good at providing real-world examples on how to use it. Does anyone know of a web page that contains some example model files?

Better still, can someone answer a question about low-order panel method programs and their use of wake planes? I am trying to model a bi-plane design and am confused on whether each wing needs a wake plane attached to the trailing edge (including the tail section). I am concerned that having multiple co-planar wake planes will give false results. Also, there was no mention of having a vertical wake plane for the vertical tail section. Do you need one? (I need this to model yaw stability.)


mlewis at (change the ' at ' to '@' to make an email address. I get enough spam already.)

Peter Cavallo May 14, 2000 11:35

Re: PMARC wake sheets
I had used PMARC several years ago, and my understanding was that you needed to have a set of wake panels off of each and every lifting surface. Thus I imagine your tail surface should also have a wake sheet.

Since PMARC is a potential flow solver, the circulation generated by each of your wings/tails must be offset by a wake sheet, which carries the opposite circulation, thus preserving irrotational flow.

The input is a little burdensome with its host of namelists I agree. Maybe the program's authors (Ashby, have something on the NASA Ames site which will help?

Good luck.

Dave Pinella May 17, 2000 14:13

Re: PMARC-12 question
Yes, you need to define a wake off of each wing as well as the elevator. You do not need a wake off of the rudder unless you are modeling rudder deflection and/oe a yaw condition.

Dave P

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