# Simulation of waves on a Water Surface

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 January 9, 2012, 02:17 Hello Sir, #21 Member   Jignesh Join Date: Aug 2011 Location: India Posts: 68 Rep Power: 8 i am trying to solve the two phase simulation of hose pipe which is located at sea so its shape becomes like wave. and continuously water and air are flow inside the one end of the pipe and the other hand is fixed. pipe is moving like wave so when the inlet end of the pipe is going above then air is come inside the pipe and when it comes down then water come inside the pipe. i got the simulation of moving mesh and also got the simulation of air and water inside the pipe with interDyMFoam. but it is for same velocity of air and water. But now i have trouble in how to give the different velocity of air and water? so plz help me. i m still waiting for ur reply. thank you very much.

 February 2, 2012, 02:10 high courant number #22 New Member   Nilesh Tank Join Date: Oct 2011 Location: India Posts: 5 Rep Power: 8 Hello Sir, I am solving 2D external aerodynamic case of simple ahmed car profile. I am using pisoFoam. deltat is 0.001. but i am getting very high courant number. I assumed Co. no. as 1 and fixed deltat. Can you please help me? Thanks & regards Nilesh

February 3, 2012, 05:04
hi Nilesh
#23
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Jignesh
Join Date: Aug 2011
Location: India
Posts: 68
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Quote:
 Originally Posted by Nilesh_87 Hello Sir, I am solving 2D external aerodynamic case of simple ahmed car profile. I am using pisoFoam. deltat is 0.001. but i am getting very high courant number. I assumed Co. no. as 1 and fixed deltat. Can you please help me? Thanks & regards Nilesh

i am happy to see that you are using openFOAM. now for your problem first u see the openFoam tutorials of lid driven cavity in that tutorial u will find your answer because in that u will find the courant number condition and its definition,

if u unable to find that then replied me ok
best wishes

Jignesh

February 3, 2012, 10:16
#24
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Join Date: Mar 2009
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Quote:
 Originally Posted by Nilesh_87 Hello Sir, I am solving 2D external aerodynamic case of simple ahmed car profile. I am using pisoFoam. deltat is 0.001. but i am getting very high courant number. I assumed Co. no. as 1 and fixed deltat. Can you please help me? Thanks & regards Nilesh
Courant number of 1 is very high, and can lead to instability when you have fine mesh or your computations require many iterations. As suggested in another post, please review the lid driven cavity example and try with the courant number there. Once you have decided on a Courant number you can determine the appropriate deltaT based on your cell size. This is also explained in the referenced example.

 September 11, 2013, 02:49 #25 New Member   Join Date: Feb 2012 Posts: 2 Rep Power: 0 Hi Guru Foamers, Will the above discussed approach work too is 'LTSInterFoam' solver is used (if main interest is on the free surface)? Thanks

 September 11, 2013, 08:24 #26 Senior Member   musaddeque hossein Join Date: Mar 2009 Posts: 309 Rep Power: 11 I would suggest that you look at the example for ltsinterfoam and determine the appropriate courant number. I have not used this solver. The example can be found at: \$FOAM_TUTORIALS/multiphase/LTSInterFoam/wigleyHul As far as I know, the solver uses local courant number. However what that number actually is, you will need to find from the example.

 September 11, 2013, 09:35 #27 New Member   Join Date: Feb 2012 Posts: 2 Rep Power: 0 Dear Musahossein, Thanks for your reply. I used this tutorial and obtained nice Kelvin wave pattern on free surface. However, I was thinking whether it is possible to use this solver to: 1. include the wind effect too, to simulate the wind generated ripples on free surface. 2. to include incoming wave (as there is sea state or something) Another concern is how to avoid boundary reflection if the simulation running for very long time or much more steps than the tutorial setting. Thought the previous discussion might be related to my doubts, any one can advise? Thanks a lot! zijun

May 22, 2015, 01:19
#28
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Peter W
Join Date: May 2015
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Quote:
 Originally Posted by ngj Hi Pierre, One more consideration with respect to the problem you describe. The solver 'interFoam' produces considerable velocities in the air, which originate from numerical inaccuracies, so you should be very careful, if you are thinking of using interFoam to study the effect of wind on the shape and other properties of surface water waves. Good luck, Niels
Hi Niels,
Firstly, thankyou for producing your excellent wave modelling package.
I am fairly new to CFD, and am trying to study wind wave /wind current interaction. If InterFOAM is a poor option, do you know of any other solver / package that is suited to wind wave interaction?
Regards,
Peter

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