Doublet Lattice FORTRAN code

[traianus]

Hello everybody,
I need a FORTRAN code (the source code) with the capability to calculate the generalized aerodynamic matrices given the modes of the structure. In particular, I need a code that is able to handle 3D structures made by assembling trapezoidal plate elements.
Does anyone have/know about codes able to solve my problem? I need the source code in FORTRAN. Please help me!
Traianus

 

[traianus]

Nobody knows a good unsteady aerodynamic code that solves my problem?

 

[traianus]

Nobody works with unsteady aerodynamcs?

 

[traianus]

Please! Your help is very apreciated!

 

[Astronuc]

This is difficult to answer because it would probably involve some proprietary software.

I believe CFX (http://www-waterloo.ansys.com/cfx/ ) and Star-CD (http://www.cd-adapco.com/products/starsolver.htm), which are both CFD codes, are written in FORTRAN. They are generic CFD and IIRC have some fluid-structure interaction capability. I am not sure if the source code is available, even if only a specific module.

Otherwise, the aircraft manufacturers like Boeing and Lockheed have their own proprietary software and you would be unlikely to get the FORTRAN.

Contact ANSYS and Adapco to see what you might be able to obtain.

 

[traianus]

Thank you. I really need the source code...

 

[PerennialII]

... been looking at the post for a while but haven't come up with anything really good, could you elaborate a bit on the actual problem & what implementations in detail you'd be needing?

I need a code that is able to handle 3D structures made by assembling trapezoidal plate elements.

Meaning, do you require the whole scheme starting from model generation etc. ? Or some "bits and pieces" like the specific solver part etc. Might try to patch something.

 

[traianus]

Thank you for your question. I explain what I need with the simplest case. Suppose I have a non-planar wing configuration such as a biplane with (just for simplicity) rectangular wings. Suppose that I like to perform the unsteady subsonic (incompressible is fine) aerodynamic analysis by using a good doublet lattice code. This code should be able to take the natural modes (for example the first 20 modes) and calculates the generalized aerodynamic matrices (in the frequency domain) given a set of (for example 10) reduced frequencies. So, the doublet lattice code I need should be in FORTRAN, and should be able to hundle this case (or similar non-planar configurations). I must have the source code of it because I have to integrate it in a much more complex aeroelastic code.
Thank you,
Traianus

 

[PerennialII]

What online sources have you checked ... you've checked like:

http://www.cfd-online.com/Links/soft.html
http://www-berkeley.ansys.com/cfd/CFD_codes.html

 

[traianus]

Thank you for your links, but I did not find the source code in FORTRAN of a doublet lattice code. I only found a vortex lattice code which is unuseful because I have written a vortex lattice code and now I need the unsteady part.

 

[PerennialII]

Thank you for your links, but I did not find the source code in FORTRAN of a doublet lattice code. I only found a vortex lattice code which is unuseful because I have written a vortex lattice code and now I need the unsteady part.

Yep, I noticed the same. I'll dig a bit deeper into a couple of source repositories, perhaps will get lucky.

 

[traianus]

Nobody knows? I think that this code could be useful for all the comunity

 

[G. Kretzschmar]

unsteady subsonic aerodynamics

We have just the same problem. Seeking for a code (preferentially but not necessarily FORTRAN), we were delighted to find the forum. All we know is that "a big European aircraft manufacturer" has recently given a contract to a software developper to write a code for unsteady subsonic aerodynamics for bodies which are not "infinitly thin", that means thick airfoils, nacelles, and fuselages.

We would highly appreciate any information about an accessible code or at least papers where the theory is fully explained. We are not in a hurry and could envisage to start our own programmation - and why not in cooperation with others?

G. Kretzschmar

 

[traianus]

Hello Kretzschmar,
I know a very good report about DLM. It is detailed for PLANAR wings (no 3D configurations that I would need). The report is

"A COMPILATION OF THE MATHEMATICS LEADING TO THE DOUBLET-LATTICE METHOD"

Max Blair
WL-TR-95-3022

 

[PerennialII]

One pretty recent online source came about & might be of some use:

http://www.smr.ch/local/doc/reports/ws2002/PaulArendsen.pdf

 

[traianus]

Thank you PerennialII. But I have problems to see the PDF. It has a lot of strange characters and formulas are bad. Is it the version of my ACROBAT (6.0)? Can you read it well? Which ACROBAT reader do you have? Thank you!

 

[PerennialII]

... I've 7.0.7 and it looks good, equations and all. Probably easiest to try to upgrade.

 

[traianus]

Thank you. But what I really need is at least a detailed theory about the nonplanar case. For example, the paper I posted is amazing for the planar case only.

Anyway, I am going to upgrade my acrobat soon.

 

[traianus]

Hello,
I decided to write my own doublet lattice code for nonplanar surfaces with zero thickness.
I need from you an help for the SYMMETRY condition (I like to model half airplane!). How do I do that? For the vortex lattice I know it, but for the doublet lattice case I am not so sure.

 

[G. Kretzschmar]

I had to postpone work on the topic for a long time. Now I am back to the forum and would like to thank the colleagues for their help by communicating useful references.

Thanks!

G. Kretzschmar

 

[traianus]

You are welcome.
I programmed my DL code with 3d capability, but I am not completely satisfied with the quasi-singular problems for nonplanar wings. I will work on it in the future.