Hi guys,

I hope I'm in the right place. Considering I'm starting from scratch, what tools and knowledge do I need to develop a transonic aeroelastic CFD code for an oscillating airfoil? My knowledge of CFD stops at the J. D. Anderson textbook, which I believe is very good introduction.

The book of fung on aeroelasticity would be a good place to begin with.I remember reading about the transonic aeroelasticity in there.The book is titled

" An introduction to the theory of aeroelasticity" By Y. C. Fung.

Hi Nicholas, What kind of problem are you trying to solve? 2D, 3D, steady or unsteady? Do you have any preferences for which type of transonic code you want to develop - such as Euler, Full Potential or Transonic Small Potential ?

Hi B, I'm trying to solve for 2-D unsteady transonic flow around an oscillating airfoil, probably a NACA 0012. I would like to start with an Euler transonic code so that I could at least capture the non-linear behaviour of the fluid flow. Then in future, I could work have a try at a Navier-Stokes code. Could you give me some advice on how to go about this at all?

I know that Yoshihara (sp?) developed an unsteady Euler code in the late 70's that might be useful for your problem (it's no doubt been massively improved since). From personal experience I'd advise against using the Transonic small disturbance formulations as they're notoriously unstable for aeroelastic work (unless you want to use a very coarse grid or a very small timestep).

Hope this is of some help, B

Is it possible to get hold of this code or detailed information on how this code was developed?

Hi, some commercial codes are now available for FSI problem. I know FASTRAN for example. you can use otherwise CFX and Ansys or ADINA (I think). If you want some info have a look at my publications on www.aero.polimi.it/~cavagna I hope it helps. Regards Luca

I don't know if there's a publicly available euler method to solve transonic flows. To work out how the code was developed I'd suggest looking up the Yoshihara papers for the early stuff and perhaps doing a citation search to find out who's developed their method since then. I'm away from the office at the moment but I'll try to get hold of the original reference when I get back.

There is a publicly available 2D transonic small disturbance code (steady) called Tsfoil (a google search will find this easily). It's written in an early version of fortran and is about 5000 lines long (if memory serves). I tried to use it a couple of years ago but never got it to work properly - it isn't clear from the source code what the program is actually doing and the input files are missing; I'd imagine you'd need a very good knowledge of both fortran and the small disturbance theory to get it to work. In which case it'd probably be easier to develop a code of your own that decipher someone else's. The old versions of fortran take some getting used to as well which complicates matters.

I don't if there are any publicly available full potential or Euler codes. I have heard that these codes are still in use for some modern research (Boeing apparently still use full potential codes for some of their design work) so I'm guessing that most worthwhile codes would be proprietary software and not available to us (

A good place to start looking for Euler methods might be:

R. Magnus and H. Yoshihara, 'Inviscid transonic flow over airfoils', AIAA J., 8, 2157-2161 (1970).