Help! 3d hess smith panel method
 

Dear all :):

I am doing the research of numerical investigation about the potential flow around hydrofoil.

I use Hess and Smith panel method as my basic method (airfoil), I have finished 2D source and vortex NACA airfoil programming with FORTRAN 90. and trying to continue to 3D case, however, I nearly have no progress on that after two months programming.

So I hope someone if they can provide some help on 3D code thing for airfoil or other shape.

I have read the book of low speed aerodynamics written by Katz, the programming 14 in appendix is incorrect or there maybe some wrong cause I had tried it, it doesn't work.

I am so appreciate if someone can give me some help!

Thank you very much! :)

zhong

Try XFLR5, it has lifting line, VLM and 3D panel models included:

http://xflr5.sourceforge.net/xflr5.htm

You can also search after PANAIR on the NASA website, if I remember correctly you can find the complete documentation (including theory).

Do

Hi, Do

Thank you very much for your help!

I have checked the two information u provided, the first one I think is software, but now I am trying to make the FORTRAN programming, but I think it will be helped later.

I think PANAIR is one can help me a lot, but do u think where I can find this program or is it possible to find it on internet, also, the programming I am doing is using low order panel method (PANAIR I think is based on the higher order panel method), can u give me some advise and help on that?

Thank you very much!

zhong

Hmmm ... you can buy Panair from this website (basically it is a CD full with a lot of small Fortran codes from NASA now in the public domain):

http://www.pdas.com/

For the theory part I think the book of Katz and Plotkin is the best reference you can find, ignore the software from the book, this was implemented by students, so you can't expect high quality but the code should work.

Do

Lol, u mean the programming 14 in appendix works? have u tried about that? cause I write it all down in FORTRAN, but it seems doesn't work, is it the publish problem?

I am agree with u that the theory in that book is the best one, I really hope the code after does work, so u know where the problem is in that code?

zhong

What do you mean but "it does not work" ? Do you have a specific problem ? Send me the error you encounter and the name of the Fortran compiler you use, maybe I can help you,

Do

Other panel code theory options are VSAERO and PMARC. You can find information on both codes at ntrs.nasa.gov. Both codes are lower order panel methods. PMARC is based on VSAERO. I would suggest you start with VSAERO's theory documentation which can be found on ntrs and then go onto PMARC. Then, if you must, go on to PANAIR. PANAIR is very complex. If you are interested in incompressible flow, then VSAERO/PMARC are probably the way to go, unless you have multiple bodies in close proximity to each other (i.e. panels seeing panels). If you are interested in subsonic compressible flow, then PANAIR is the better way to go, but, by how much is debatable. For supersonic flow, PANAIR is the choice. A US citizen can purchase PMARC from Open Channel, but at $700, I don't think it is cheap for non company use. One can also buy source code for Cmarc from www.aerologic.com for $625.

Thanks Martin,

Yes, my research is only focus on the low order panel method and incompressible flow, this code is what I will used as hydrofoil which sailing in the water, so I think subsonic in aerodynamics is enough.

Lol, that much, unfortunately, this is my own uni research, it is not company use.

Do u know the code in hess and smith panel theory?

Sorry, only what I come across on the internet.

Frankly, I'm not sure what the difference between Smith and Hess 3D panel methodology and VSAERO/PMARC is. The differences could be in the panel formulation and/or how the codes set up the boundary conditions. For VSAERO, the panels are low order (constant source/sink and vortex ring). VSAERO boundary conditions are no flow through the body (i.e. v dot n = 0) and free stream potential on the inside. This results in knowing the source strength distribution without having to solve a matrix. It is a simple expression. The doublet strength (in this case vortex rings) is then solved by a matrix where the right hand side takes into account the freestream velocities and perturbations from the sources/sinks. The basic methodology is straight forward.

This can be found in "Program VSAERO theory document: A computer program for calculating nonlinear aerodynamic characteristics of arbitrary configurations" on ntrs.nasa.gov

The problem is I put all code in FORTRAN, but it says floating point error, invalid!

Can you attach the Fortran code ? I will test it with my compiler. I suppose you have copied exactly the code from the book.

Do

Have you tried emailing Dr. Katz and asking him for the source code?

Edit: this post was directed at zhongzu.

There is also a free open-source 3D panel code in FORTRAN as well as user friendly environment called AVL by Mark Drela and Harold Youngren. It can be downloaded for free from

http://web.mit.edu/drela/Public/web/avl/

Truffaldino

@truffaldino AVL is actually a VLM code, like Tornado and many others open source codes out in the wild.

Thank you, can you tell me if it is work after your try.

I did not attach the code, only write it in the FORTRAN. and I checked a few times, it seems I write it excatly the same as that book provides.

zhong

Yes， Martin, That is good idea, I think I will try today!

The idea was to "try" your code and not to write it myself :) so please attach the Fortran code if you want me to try it.

Do

Dear Matin
Hi!
I have looked anywhere for VSAERO but nothing was found. So I knidly would like to ask if the sfotware couples 3D panel method and Boundary layer and if they consider viscous effect as well.
Finally, I could not find the source code so any one can show me where is it because it is really interesting software I suppose.

Thank you in advance.

Another possibility: XFLR5 is a free 3D software which includes several options: Lifting line, VLM or 3D panel method coupled with viscous analysis of x-foil. I think source code is in C++ and is available for free.