badpilot27
New member
I want to start 3d printing some more complex planes and I want a decent free CFD software to help me design those planes. I'm wondering if I can get some suggestions on what software to use.
Help! finding a CFD software
- Thread starter badpilot27
- Start date
NickRehm
Member
xflr5 is technically not CFD but is a free and common aero analysis package that uses the vortex lattice method: https://www.xflr5.tech/xflr5.htm
Another similar option is openVSP: https://openvsp.org/
Another similar option is openVSP: https://openvsp.org/
telnar1236
Elite member
Before doing any CFD, it's probably worth being familiar with at least a bare minimum of the mathematical framework behind fluid dynamics. CFD can give some real nonsense answers, so unless you know about what it should be saying, you might get a result that makes no sense. Also, a lot of stuff you can determine in CFD is way easier to do by hand. It is absolutely possible to learn CFD with no professional training, but it would definitely take some doing. That said, here are some free options.
XFLR5 is great and has a relatively low barrier to entry compared to a lot of CFD. It's a good place to start, and to be honest, for most rc planes, it's as good as you will ever realistically need. It's right on the border of CFD, but it does meet the bare minimum definition in that it is a finite element computation of fluid dynamics, but it is mostly restricted to analysis of wings and wing-like shapes, like tails etc. There is functionality to analyze fuselages, but it is extremely unreliable and barely works to the point that I have never used it apart from playing around a bit.
XFLR5 results
XFLR5 results
Another option, specifically for airfoil analysis is XFOIL, but it is integrated into XFLR5 so unless you have a seriously limited computer, there's not much reason to use it. XFOIL does have a very useful tool for modifying airfoil dat files I frequently use for evaluating flap performance. AVL (Athena Vortex Lattice) is made by the same people as XFOIL for stability and control analysis. It's a bit more capable than anything in XFLR5, but for most purposes there is little reason to use it. Both XFOIL and AVL are not remotely user friendly since they need to be run from the command prompt.
XFOIL run - the window on the right is all the GUI you're getting
For more complex things, I personally use the free version of SimFlow. It's about as good a full-featured CFD software as I'm aware of without spending a ton of money. The big limitation here is that your meshes can only be up to 200,000 nodes in the free version which takes some real working around. I generally run symmetry models unless I'm trying to evaluate something with sideslip angles since it makes it far easier to stay within that limit.
sim-flow.com
SimFlow Results - streamline plot of F-104 symmetry model
But for CFD, keep in mind, your results are only as good as what you put in. Garbage in, garbage out. XFLR5 is generally pretty friendly in that the answers it gives you won't be total BS unless you really mess around with the settings, but with SimFlow you can very easily click buttons and get AN answer, but it might be the complete opposite of what will really happen.
XFLR5 is great and has a relatively low barrier to entry compared to a lot of CFD. It's a good place to start, and to be honest, for most rc planes, it's as good as you will ever realistically need. It's right on the border of CFD, but it does meet the bare minimum definition in that it is a finite element computation of fluid dynamics, but it is mostly restricted to analysis of wings and wing-like shapes, like tails etc. There is functionality to analyze fuselages, but it is extremely unreliable and barely works to the point that I have never used it apart from playing around a bit.
XFLR5 results
XFLR5 results
Another option, specifically for airfoil analysis is XFOIL, but it is integrated into XFLR5 so unless you have a seriously limited computer, there's not much reason to use it. XFOIL does have a very useful tool for modifying airfoil dat files I frequently use for evaluating flap performance. AVL (Athena Vortex Lattice) is made by the same people as XFOIL for stability and control analysis. It's a bit more capable than anything in XFLR5, but for most purposes there is little reason to use it. Both XFOIL and AVL are not remotely user friendly since they need to be run from the command prompt.
For more complex things, I personally use the free version of SimFlow. It's about as good a full-featured CFD software as I'm aware of without spending a ton of money. The big limitation here is that your meshes can only be up to 200,000 nodes in the free version which takes some real working around. I generally run symmetry models unless I'm trying to evaluate something with sideslip angles since it makes it far easier to stay within that limit.
CFD Software | SimFlow CFD 2024 - Free Download Now!
SimFlow CFD Software for your everyday CFD Simulations. Computational Fluid Dynamics (CFD) Analysis Software. Download SimFlow for Free.
But for CFD, keep in mind, your results are only as good as what you put in. Garbage in, garbage out. XFLR5 is generally pretty friendly in that the answers it gives you won't be total BS unless you really mess around with the settings, but with SimFlow you can very easily click buttons and get AN answer, but it might be the complete opposite of what will really happen.
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