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Pong Tato November 13, 2008 20:24

Flow around ship
 
I'm trying to simulate flow around a ship hull to calculate skin friction resistance, viscous pressure resistance, and wave making resistance using CFX. How can I get the value of wave making resistance, viscous pressure resistance, and skin friction resistance from the post processor of CFX ?. How to calculate them individually ?. How about drag force in CFX, Is it wave making resistance,or viscous resistance, or skin friction resistance ? Thank you very much for everyone in this forum.

Chebeba November 16, 2008 17:43

Re: Flow around ship
 
You get the total drag as the force_x() function on your hull surface (if the ship is travelling in the X direction)

You can't really as far as I know separate out the wave resistance.

To separate viscous and pressure drag you have to look at the monitor output at the end of the simulation, where the report will include those numbers.

I have not found any readymade CEL function to separate those, although you could calculate them using the integration functions in CEL.

It is a good idea to monitor force_x@hull during the simulation to make shure you have convergence. This type of simulation converges very slowly. I typically run about 100hrs wall clock time on a 20 core cluster with a 6M element mesh to get wavfe pattern convergence.

Pong Tato November 16, 2008 21:56

Re: Flow around ship (To Mr/Mrs Chebeba)
 
Thank for your information. If you don't mind please send me tutorial how to modelling flow around ship to my email address at c.mocca@yahoo.co.uk. I'm so thankful for your information.

khabiran September 18, 2011 10:30

hi
it is easy... by these step...
1. solid your ship and insert into CFX (modeler)
2. make your domain and subtract your ship from domain
3. make imperial face (by extrude a line for a face by type imperial )
4. make your mesh (automatic)
5. illustrate inlet,out let flow and wall and run
have a best day


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