CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM (https://www.cfd-online.com/Forums/openfoam/)
-   -   Is OpenFOAM right software for whrilpool simulation (https://www.cfd-online.com/Forums/openfoam/109975-openfoam-right-software-whrilpool-simulation.html)

dcarden December 1, 2012 21:57

Is OpenFOAM right software for whrilpool simulation
 
I'm a complete beginner at engineering or CAD software. I'm looking for something that could be used to model whirlpools, and wondering if this would be the right software for the job.

On an episode of Mythbusters, they built a whirlpool simulator using a large water tank with a drain out the bottom. They then hooked up a large water pump to the outlet hose of the bottom of the tank, and pumped the water bank into the tank through the open top.
http://www.youtube.com/watch?v=yYsPyguu7cc

I'm looking for a software to model this type of setup. I'd like to be able to change up the water inlet, drain properties, tank size and shape and so on to model the affect on the whirlpool.

Before I spend a lot of time going through the tutorials and manuals and such to learn the software I thought I ask the community first if I'm on the right track. I'd appreciate any feedback on if this is an appropriate software to use for this purpose, as well as any pointers or advice on getting started for this specific purpose. Suggestions on other, preferably open source or otherwise reasonably priced software packages that might be more appropriate would also be appreciated if OpenFOAM is not the right (or best/easiest to learn) tool for the job.

Thanks :)

The King December 2, 2012 14:06

Yes, you can. But the question is what do you want to calculate? The software will provide you a lot of detailles, water level, velocity/pressure/turbulence on all points in your model. One of the first tutorials is a dambreak, use that as a start-point for your simuation. Succes!

dcarden December 2, 2012 22:54

I'm not looking to calculate anything, as such. More that I'd like to be able to visually model the "whirlpool machine". It's a kind of water fountain, visual art, "sculpture" type of idea that I have that I'm looking for a way to model in a simulation type environment before starting on real world prototypes.

elvis December 3, 2012 13:14

Hi,

principly OF is capable of simulating your whirlpool with fountains etc.
But it is quite challenging to get to such a level and the learning curve is quite steep.

If you want to design and visulise your whirlpool you might be happier with blender.
http://www.blenderguru.com/videos/in...uid-simulator/
http://wiki.blender.org/index.php/Do.../Physics/Fluid
blender's fluid sim tool uses LBM-method => http://elbeem.sourceforge.net/

Usability of Blender and elbeem is much better than OF. But real world physics are much better modeled with OF, but at the cost of a much steeper learning curve.

If you are not afraid to learn program a solver in OF for your whirlpool sim, take a look at helyx OS as a GUI-tool to mesh your whirlpool.

Or if take a look at SwiftBlock
SwiftSnap for other free GUI meshing tools, but that is only the meshing, you need to program your solver

dcarden December 4, 2012 23:05

Thank you for the suggestions. I'm going to take a closer look at Blender. From that tutorial video, it looks like it may be what I'm looking for.

kwardle December 7, 2012 11:43

I agree with Elvis, if you are just looking for something that looks like a whirlpool visually and do not care about the quantitative accuracy, then Blender's fluid simulation module is the way to go. There will be a learning curve there too, but there are good tutorials to get you started.
-Kent

dcarden December 7, 2012 23:15

If by quantitative accuracy you mean getting accurate "real world physics" type water flow, then I have to go back to wondering if Blender would be the right platform.

I found a better example of what I'm looking to try and make (though I'd be going the opposite direction with the water flow)

http://blog.makezine.com/2010/10/06/whirlpool-fountain/

Since I'd likely be also using acrylic or something similar, having to retool, mold, and cast to make tweaks to the shape to try and get the whirlpool looking the way I like would like could be a bit tedious. So part of what I'm looking for is to be able to get as close to accurate a model of how things are going to look through simulation.

elvis December 10, 2012 03:12

Hi,

Lattice Bolzmann Method (LBM) (like that what is used in Blender) is known to be not as accruate as Finite Volume Method (FVM), but many can live with that, because the method is faster from the calculation speed and the the demand of the computational power is lower.

BMW for example is a big LBM-user (Powerflow) for their CFD-simulations, but I saw one of their CFD-engineers (back in 2007) from "BMW-Sauber F1-Racing" (that raceing-division is not existing anymore) at 2nd OpenFOAM-workshop 2007 in Zagreb ;-)! When it comes to the last digits FVM rules.

If I were you I would give Blender a try, much more user manuals and so on! And your results can be beautyfully rendered within Blender!

mturcios777 December 10, 2012 13:55

We had a guy from Exa talk to us about Powerflow. Seemed like an interesting tool, but its not very good for us because of the Mach number limitation (can't do much for Ma > 0.4).


All times are GMT -4. The time now is 12:19.