Solving for two phase, incompressible, inviscid flow (OpenFOAM)

Betsy · June 14, 2012, 23:27

Hello - I would like to solve for incompressible, inviscid flow (Euler Equations) for two phases (waves, NOT bubbles) in OpenFOAM. I am considering 3 options and I could use some advice on which may produce the best results or what problems I may run into:

1) Simply use interFoam and set viscosity to approximately zero (i.e. 1E-10 or something like this)
2) Write a new solver based on interFoam removing the viscous term in the Navier-Stokes equation
3) Use twoPhaseEulerFoam - although I am reluctant to use this solver since it is more difficult for me to see exactly how the solver is working and it seems to be geared more towards bubbles.

Any advice is appreciated.
Sincerely,
Betsy

Betsy · June 15, 2012, 19:32

As a follow up - does OpenFOAM use Reynolds number to non-dimensionalize the equation? If so, then this would cause problems with setting viscosity to approx. zero.

akidess · June 16, 2012, 07:58

No, OpenFOAM works with the dimensional equation. Keep in mind that setting the viscosity to zero or something very small will make the problem "stiff", i.e. make it tougher to obtain a stable numerical solution.

robbirobocop · June 18, 2012, 18:06

I would use interFoam. I have already seen some bachelor/master thesis that successfully simulated waves (i.e. at/around ships).
However writing your own solver might not be such a problem as well, the wiki gives some good hints on how to modify and expand solvers...

Ralph M · June 27, 2012, 17:08

Depending on which kind of waves you want to simulate I'd suggest you to have a look into the LTSInterFoam solver which would be of use for semi-static problems.

ehsan · July 15, 2012, 02:52

Dear All,

Please see Eq. 4 in the paper below:

http://www.marinepropulsors.com/proc...0Propulsor.pdf

May I ask you whether in OpenFOAM the same equation including turbulence effects are used for viscosity of two phase flow or only simple averaging from laminar values are employed?

Thanks

pablodecastillo · July 16, 2012, 06:58

Hi Betsy,

Just remove the viscous terms from interFoam, and it is going to work pretty well.

June 14, 2012, 23:27	Solving for two phase, incompressible, inviscid flow (OpenFOAM)	#1
Betsy New Member Betsy Seiffert Join Date: Feb 2011 Location: Honolulu, HI Posts: 11 Rep Power: 15	Hello - I would like to solve for incompressible, inviscid flow (Euler Equations) for two phases (waves, NOT bubbles) in OpenFOAM. I am considering 3 options and I could use some advice on which may produce the best results or what problems I may run into: 1) Simply use interFoam and set viscosity to approximately zero (i.e. 1E-10 or something like this) 2) Write a new solver based on interFoam removing the viscous term in the Navier-Stokes equation 3) Use twoPhaseEulerFoam - although I am reluctant to use this solver since it is more difficult for me to see exactly how the solver is working and it seems to be geared more towards bubbles. Any advice is appreciated. Sincerely, Betsy

June 16, 2012, 07:58		#3
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 30	No, OpenFOAM works with the dimensional equation. Keep in mind that setting the viscosity to zero or something very small will make the problem "stiff", i.e. make it tougher to obtain a stable numerical solution. __________________ On twitter @akidTwit Spend as much time formulating your questions as you expect people to spend on their answer.

June 27, 2012, 17:08		#5
Ralph M Senior Member Ralph Moolenaar Join Date: Aug 2010 Location: 's-Hertogenbosch, the Netherlands Posts: 120 Rep Power: 16	Depending on which kind of waves you want to simulate I'd suggest you to have a look into the LTSInterFoam solver which would be of use for semi-static problems. __________________ CFD for marine applications? Go to http://www.marinecfd.com/ and join the OF Ship Hydromechanics Group: http://www.cfd-online.com/Forums/gro...mechanics.html

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June 15, 2012, 19:32		#2
Betsy New Member Betsy Seiffert Join Date: Feb 2011 Location: Honolulu, HI Posts: 11 Rep Power: 15	As a follow up - does OpenFOAM use Reynolds number to non-dimensionalize the equation? If so, then this would cause problems with setting viscosity to approx. zero.

June 18, 2012, 18:06		#4
robbirobocop Member Rob Join Date: Sep 2011 Posts: 55 Rep Power: 15	I would use interFoam. I have already seen some bachelor/master thesis that successfully simulated waves (i.e. at/around ships). However writing your own solver might not be such a problem as well, the wiki gives some good hints on how to modify and expand solvers...

July 15, 2012, 02:52		#6
ehsan Senior Member Ehsan Join Date: Mar 2009 Posts: 112 Rep Power: 17	Dear All, Please see Eq. 4 in the paper below: http://www.marinepropulsors.com/proc...0Propulsor.pdf May I ask you whether in OpenFOAM the same equation including turbulence effects are used for viscosity of two phase flow or only simple averaging from laminar values are employed? Thanks

July 16, 2012, 06:58		#7
pablodecastillo Senior Member Pablo Join Date: Mar 2009 Posts: 102 Rep Power: 17	Hi Betsy, Just remove the viscous terms from interFoam, and it is going to work pretty well.