CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

free-surface condition for moving fluid in potentialFreeSurfaceFoam

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 30, 2013, 14:01
Default free-surface condition for moving fluid in potentialFreeSurfaceFoam
  #1
New Member
 
Join Date: Sep 2013
Posts: 10
Rep Power: 13
simon-2 is on a distinguished road
Hi,

I tried to use potentialFreeSurfaceFoam on a ship resistance test case. The case setup is quite similar to the WigleyHull Tutotial, thus a rectangular blockMesh including a static hull shape (trim&sinkage neglected) and some refinements (surface and around the hull) made by snappyHexMesh. The hull remains static while velocity is applied to the Fluid. Different to the WigleyHull, i used a symmetryPlane in y=0 to simulate one half only.

unfortunately, the waves generated do not behave as expected- it seems the waveSurfacePressure Boundary doesn't consider fluid motion, i.e. the waves don't drift downstream, as they should, but rather disperse radially as if the fluid was static. (while on a real ship, the fastest wave is dispersing as fast as the ship speed, thus can not "overtake" the hull).


Initial/boundary conditions are
U:
internal: fixedValue uniform (shipSpeed 0 0)
inlet: fixedValue uniform (shipSpeed 0 0)
walls: fixedValue uniform (shipSpeed 0 0)
hull: fixedValue uniform (0 0 0)
freeSurface: inletOutletParSlipVelocity (as in "oscillatingbox" tut)
outlet: zeroGradient
centerplane: symmetryPlane

p_gh:
internal: uniform 0
freeSurface: waveSurfacePressure (as in "oscillatingBox" tut)
centerplane: symmetryPlane
all others: zeroGradient

p:
"calculated" for all (except of centerplane which is still symmetryPlane)

i have tried out some other similar boundaries (esp for walls and outlet), but could not eliminate the problem, so now i suspect the waveSurfacePressure boundary to be the reason (but there is no other one for use with potentialFreeSurfaceFoam.?).

I tried to modify this Boundary to do the job- without success yet. At least, i could coarsely cope with the syntax and got a modified version ("waveFreeSurfacePressure" ) compiled and running, but not working (i guess i'm lacking the necessary cfd backgrounds ).

Can anyone help me how to modify waveSurfacePressure to cope with fluid motion (like U∞ in publications)? maybe mapping the waveheight changes to a position which is located dt*U∞ downstream, or using a phi field which is relative to fluid motion or similar?

Has anyone else used potentialFreeSurfaceFoam for ship resistance before, or at least in a case with a moving fluid?

Ideas if anything else could be wrong to cause this phenomena?

Thanks,
simon
simon-2 is offline   Reply With Quote

Old   November 17, 2014, 19:06
Default
  #2
New Member
 
Join Date: Nov 2014
Posts: 11
Rep Power: 12
bizzy is on a distinguished road
Hi Simon,

i has been a long time, but could you solve the problem? I also set up a case and am facing the same problem, the waves are generated at the hull and then move in forward direction as if there was no moving fluid.
bizzy is offline   Reply With Quote

Old   November 18, 2014, 06:44
Default
  #3
New Member
 
Join Date: Sep 2013
Posts: 10
Rep Power: 13
simon-2 is on a distinguished road
Hi Bizzy,

I'm not sure if it is possible with this Foam at all- i finally gave up and solved my problem with interFoam (static hull) and interDyMFoam, respectively (considering trim&sinkage).

What i guess is that pfsf is not capable of simulating a moving fluid. I would prefer it to interfoam as it could save so much computation time, but i was not successful with it- sorry

best regards
simon-2 is offline   Reply With Quote

Old   November 18, 2014, 19:03
Default
  #4
New Member
 
Join Date: Nov 2014
Posts: 11
Rep Power: 12
bizzy is on a distinguished road
Hi Simon,

thanks for your answer. I will let you know, if I ever find a way to do this, though.

Greets
bizzy is offline   Reply With Quote

Old   February 25, 2016, 04:55
Default
  #5
Senior Member
 
Baris (Heewa)
Join Date: Jan 2013
Location: Japan
Posts: 130
Rep Power: 13
shipman is on a distinguished road
Hi Bizzy and simon,

Is there any progress about the above mentioned probleem.

If so, please could you also share with me.

Thank you.

B
shipman is offline   Reply With Quote

Old   November 19, 2020, 21:51
Default
  #6
Senior Member
 
Claudio Boezio
Join Date: May 2020
Location: Europe
Posts: 137
Rep Power: 7
Ship Designer is on a distinguished road
Hello,

See this post for what I learned about potentialFreeSurfaceFoam: potentialFreeSurfaceFoam for ship resistance estimation

Cheers
Ship Designer is offline   Reply With Quote

Reply

Tags
free surface flow, potentialfreesurfacefoam, wave making resistance, wave solution; bc


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CFX convergence issues with free surface adenlan CFX 3 September 2, 2011 07:43
Free surface boundary condition in the VOF metod ves Main CFD Forum 2 March 8, 2011 16:23
RIPPLE's free surface boundary condition alongalong2 Main CFD Forum 4 February 10, 2011 00:35
Free surface VOF (fluid render effect) franco STAR-CD 1 July 20, 2009 06:42
CFX4.3 -build analysis form Chie Min CFX 5 July 13, 2001 00:19


All times are GMT -4. The time now is 22:29.