Aircraft Propeller model
- Dan Turner
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12 years 9 months ago #6366
by Dan Turner
Aircraft Propeller model was created by Dan Turner
Hi Guys, I'm an aerospace engineering student and one of the projects I'll be doing next year will be based on aircraft design so part of what I would like to do would be to make a basic CAD model of the design and run all the relevant analysis etc. But I was wondering if anyone had any suggestions on how I could simulate a single engined aircraft with a propeller. I know that I could make the fluid swirl relative to the model but I was wondering if there is some way I could simulate a similar effect but showing the actual effect of the propeller on the fluid?
Any help/suggestions would be hugely appreciated.
Thanks to all
Dan
Any help/suggestions would be hugely appreciated.
Thanks to all
Dan
- CAVT
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12 years 9 months ago #6367
by CAVT
Replied by CAVT on topic Re: Aircraft Propeller model
I asume that you want to analyze static longitudinal characteristics of an aircraft. Since you seem to never have done this kind of calculations, thisis the best to start with. In this case, a vortex latice method or panel method are best indicated as a starting point, but probably you may want to do an Euler or Navier-Stokes calculation.
Well, modelling a full aircraft is no joke, your cad model should be as feature-less as you can, as that would mean less effort when meshing. Meshing is actually (from my short experience at least) the most difficult part of the simulation.
In this first step you can model the propeller as a simple disc with each face as an inlet. One face has one velocity and the other face a different velocity, just like in classical propeller disc theory (you can usually give a velocity profile also, for example to model varying local lift). Presto, that's all you need to start, swirling is not as important as you may think in this etape. Besides, modeling the swirl would be more CPU consuming. I don't know about OpenFoam, but Code Saturne has some kind of fan premodeling available, you may want to dig into that.
Other tip, since in an aircraft at low angles of attack you usually don't have flow separation, you can spare some precision in the final results (specially for drag) and model only half of the aircraft and impose a symmetry condition, you'll cut down runtime by more than 50%.
If you wish to go after panel methods, modelling the propeller is a bit different, as it is made with vortex rings, but I haven't seen this implemented on out of the box open source codes, maybe PanePro has it already.
I hope this was useful. Happy simulations.
Well, modelling a full aircraft is no joke, your cad model should be as feature-less as you can, as that would mean less effort when meshing. Meshing is actually (from my short experience at least) the most difficult part of the simulation.
In this first step you can model the propeller as a simple disc with each face as an inlet. One face has one velocity and the other face a different velocity, just like in classical propeller disc theory (you can usually give a velocity profile also, for example to model varying local lift). Presto, that's all you need to start, swirling is not as important as you may think in this etape. Besides, modeling the swirl would be more CPU consuming. I don't know about OpenFoam, but Code Saturne has some kind of fan premodeling available, you may want to dig into that.
Other tip, since in an aircraft at low angles of attack you usually don't have flow separation, you can spare some precision in the final results (specially for drag) and model only half of the aircraft and impose a symmetry condition, you'll cut down runtime by more than 50%.
If you wish to go after panel methods, modelling the propeller is a bit different, as it is made with vortex rings, but I haven't seen this implemented on out of the box open source codes, maybe PanePro has it already.
I hope this was useful. Happy simulations.
The following user(s) said Thank You: Dan Turner
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12 years 9 months ago #6368
by Dan Turner
Replied by Dan Turner on topic Re: Aircraft Propeller model
I had already planned to make the CAD model very crude and to use symmetry in the simulations but I had never thought to model the propeller in that way so thank you for that suggestion. and I will also look into the code-saturne area.
thank you
thank you
- Matthew Bondy
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12 years 9 months ago - 12 years 9 months ago #6374
by Matthew Bondy
Replied by Matthew Bondy on topic Re: Aircraft Propeller model
OpenFOAM might make meshing much easier. It has a pretty darn good fairly automated mesher (referred to as 'snappy hex mesh').
It is not the easiest software to learn in some ways, I have not looked in some time but there were a lack of good tutorials. Then again video tutorials or the like are not really all that practical or necessary with OpenFOAM since it really is terminal based.
There is also a user interface called Discretizer. It makes OpenFOAM really easy to use but it seems somewhat incomplete (last I looked at, which was some time ago). A quick look reveals a new version: www.discretizer.org/
Discretizer is part of CAELinux but it is an older version.
I have no idea if any sort of propeller model will be reasonable with OpenFOAM. In Fluent there are moving reference frame models that can be used to simulate turbomachinery. I would think that OpenFOAM must in some way allow you to study this phenomenon. It almost certainly will use features that will not be built into discretizer.
I also recently heard of a new third party GUI for OpenFOAM. I think it may also be open source. It sounded like it would be quite good. I will ask a colleague using OpenFOAM to pass along some information which I will post here.
Edit: sourceforge.net/projects/helyx-os/
Cordiali saluti,
- MJB
It is not the easiest software to learn in some ways, I have not looked in some time but there were a lack of good tutorials. Then again video tutorials or the like are not really all that practical or necessary with OpenFOAM since it really is terminal based.
There is also a user interface called Discretizer. It makes OpenFOAM really easy to use but it seems somewhat incomplete (last I looked at, which was some time ago). A quick look reveals a new version: www.discretizer.org/
Discretizer is part of CAELinux but it is an older version.
I have no idea if any sort of propeller model will be reasonable with OpenFOAM. In Fluent there are moving reference frame models that can be used to simulate turbomachinery. I would think that OpenFOAM must in some way allow you to study this phenomenon. It almost certainly will use features that will not be built into discretizer.
I also recently heard of a new third party GUI for OpenFOAM. I think it may also be open source. It sounded like it would be quite good. I will ask a colleague using OpenFOAM to pass along some information which I will post here.
Edit: sourceforge.net/projects/helyx-os/
Cordiali saluti,
- MJB
Last edit: 12 years 9 months ago by Matthew Bondy.
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