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 keepfit May 18, 2012 05:33

Ship wave Boundary Condition in OpenFoam

Generate ship-wave using BCs.

Hi OpenFoamers,

I am new to OpenFoam and trying to model ship-generated waves in waterway.

I was wondering, is there some toolbox or ship-wave BC in OF, or we just need to make a real ship mesh to create such waves.

I have been using a commercial CFD software to model different type of water waves, for instance wind-wave, water flow in river in according with velocity profile, tidal waves and so on. Boundary conditions which can generate above mentioned wave are writing in C++, and then compiled to *.DLL so that BC can be used to generated waves. I am satisfied with these results so far. However I encountered some problems to generate ship-generated waves. Because when I tried to write such BC using ship-wave theory, I found that it is very hard to do it due to the lack of equations describing behavior of ship-wave .

The first thing I considered is to generate a ship model, but the fine mesh of a typical huge cargo ship with bulb bow consists of millions of cells, and then the CFD model need to be coupled with a DEM model comprising large number of particles; however, it is nearly impossible to do this coupling simulation due to the large number of CFD cells.

So I wanna know is there some simple boundary conditions for generating ship-wave in order to save time. In such OpenFOAM BC, some of ship geometry properties can be modified, e.g. length, height, width etc.

Thanks a lot.

 daveatstyacht May 24, 2012 10:24

David,
To generate ship waves you need to include a hull in the simulation. The level of detail you use can very according to your desired accuracy from a few hundred thousand cells to millions and your computational cost will vary from an few hours to many days accordingly. I suggest you look at the LTSinterFoam tutorial wigleyhull. It will give you the basic setup of how to perform ship simulations in OF. I also suggest the pimpleDyMFoam tutorial wingMotion2D if you intend to account for trim and sinkage. Good luck with your simulations.

Regards,
Dave

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