Doublet Lattice FORTRAN code

In summary: I find a better code to solve my problem, I will let you know.In summary, somebody needs a good code to solve unsteady aerodynamic problems for bodies that are not "infinitly thin". The code should be in FORTRAN, and should be able to handle natural modes and calculate the generalized aerodynamic matrices.
  • #1
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!
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  • #2
Nobody knows a good unsteady aerodynamic code that solves my problem?
  • #3
Nobody works with unsteady aerodynamcs?
  • #4
Please! Your help is very apreciated!
  • #5
This is difficult to answer because it would probably involve some proprietary software.

I believe CFX ( [Broken]) and Star-CD (, 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.
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  • #6
Thank you. I really need the source code...
  • #7
... 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.
  • #8
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,
  • #10
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.
  • #11
traianus said:
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.
  • #12
Nobody knows? I think that this code could be useful for all the comunity
  • #13
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
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  • #14
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


Max Blair
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  • #15
One pretty recent online source came about & might be of some use: [Broken]
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  • #16
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!
  • #17
... I've 7.0.7 and it looks good, equations and all. Probably easiest to try to upgrade.
  • #18
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.
  • #19
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.
  • #20
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.


G. Kretzschmar
  • #21
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.

1. What is the purpose of Doublet Lattice FORTRAN code?

The purpose of Doublet Lattice FORTRAN code is to simulate and analyze the aerodynamics of airfoils and wings in steady, subsonic flow. It calculates the lift, drag, and pitching moment coefficients of these aerodynamic bodies, as well as the pressure distribution and velocity field around them.

2. How does Doublet Lattice FORTRAN code work?

Doublet Lattice FORTRAN code works by dividing the surface of the aerodynamic body into a grid of panels, each with a doublet source and vortex sheet. These panels are then solved using potential flow theory to calculate the aerodynamic coefficients and flow properties at each panel. The results are then combined to obtain the overall aerodynamic characteristics of the body.

3. What are the advantages of using Doublet Lattice FORTRAN code?

Doublet Lattice FORTRAN code has several advantages, including its ability to handle complex geometries, its computational efficiency, and its accuracy in predicting aerodynamic characteristics. It also allows for the analysis of multiple bodies and configurations, making it useful for a variety of applications in the aerospace industry.

4. Are there any limitations to using Doublet Lattice FORTRAN code?

While Doublet Lattice FORTRAN code is a powerful tool for aerodynamic analysis, it does have some limitations. It assumes potential flow, which means it does not account for viscous effects such as drag and flow separation. It also has limited capabilities for unsteady flow and high Mach numbers.

5. How is Doublet Lattice FORTRAN code different from other aerodynamic analysis methods?

Doublet Lattice FORTRAN code is unique in that it uses potential flow theory to analyze aerodynamics, while other methods such as CFD (Computational Fluid Dynamics) use numerical methods to solve the Navier-Stokes equations. This makes Doublet Lattice FORTRAN code faster and more efficient for certain applications, but also limits its capabilities for more complex and realistic simulations.

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