water sloshing in oscillating tank (problem using udf Define_ZONE_MOTION)

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 April 1, 2013, 01:37 water sloshing in oscillating tank (problem using udf Define_ZONE_MOTION) #1 New Member   Sumit Tambe Join Date: Feb 2013 Posts: 8 Rep Power: 13 hello everyone, I am simulating 2D sloshing of water due to oscillatory motion of a square tank. Here is a small description: model=VOF: Implict, with zonal discretization. gravity in 'y' dirctn. Tank: 0.2m x 0.2m sqaure tank, closed walls. Mesh: structured, finer at the water-air interface. filled depth: 0.04m UDF: #include DEFINE_ZONE_MOTION(fmotion,omega,axis,origin,veloc ity,time,dtime) { real velocity={0.6282*sin(62.82*time),0.0,0.0}; return; } UDF is hooked up with both of the cell zones. Walls: moving walls, with relative velocity(adjacent to cell zone) =0 m/s time-step size=0.0001 s during calculation x and y velocity residuals are remaining almost constant until I reduce momentum URF to 0.001, then after the solution rapidly converges. But water remains stationary as before. The free surface orientation does not change with time. even after 1 second of flow time. Can anybody help me out?

 April 2, 2013, 06:49 #2 Senior Member   Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22 1. Is there a space in 'DEFINE_ZONE_MOTION(fmotion,omega,axis,origin,veloc ity,time,dtime)' or just a typo? 2. It is possible that 1 sec is too short time to notice sloshing, try bit longer simulation. Last edited by vasava; April 2, 2013 at 07:20.

April 2, 2013, 08:00
#3
New Member

Sumit Tambe
Join Date: Feb 2013
Posts: 8
Rep Power: 13
Quote:
 Originally Posted by vasava 1. Is there a space in 'DEFINE_ZONE_MOTION(fmotion,omega,axis,origin,veloc ity,time,dtime)' or just a typo? 2. It is possible that 1 sec is too short time to notice sloshing, try bit longer simulation.
Yeah, its a typo.
Time is surely not an issue. Instead of trying with a moving mesh, I varied a body force. Its giving good results even for small simulation time. Just that you wont see the mesh moving. but Its fairly sufficient for the analysis.

 April 2, 2013, 08:18 #4 Senior Member   Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22 You said it first! I was just going to suggest that. So is everything fine now?

 April 2, 2013, 10:46 #5 New Member   Sumit Tambe Join Date: Feb 2013 Posts: 8 Rep Power: 13 Yup!! everything is great!

November 9, 2013, 09:24
sloshing
#6
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Puneet
Join Date: Sep 2013
Posts: 14
Rep Power: 12
Quote:
 Originally Posted by Tamsu hello everyone, I am simulating 2D sloshing of water due to oscillatory motion of a square tank. Here is a small description: model=VOF: Implict, with zonal discretization. gravity in 'y' dirctn. Tank: 0.2m x 0.2m sqaure tank, closed walls. Mesh: structured, finer at the water-air interface. filled depth: 0.04m UDF: #include DEFINE_ZONE_MOTION(fmotion,omega,axis,origin,veloc ity,time,dtime) { real velocity={0.6282*sin(62.82*time),0.0,0.0}; return; } UDF is hooked up with both of the cell zones. Walls: moving walls, with relative velocity(adjacent to cell zone) =0 m/s time-step size=0.0001 s during calculation x and y velocity residuals are remaining almost constant until I reduce momentum URF to 0.001, then after the solution rapidly converges. But water remains stationary as before. The free surface orientation does not change with time. even after 1 second of flow time. Can anybody help me out?
sir i m facing same problems...how did u rectify those..plz help me out

 May 16, 2014, 08:42 #7 New Member   Join Date: May 2014 Posts: 1 Rep Power: 0 Sumit, Can you please let me know how to go about solving this problem Thanks,Samwize

November 23, 2021, 06:52
#8
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Join Date: Apr 2017
Posts: 3
Rep Power: 9
Quote:
 Originally Posted by Tamsu Yeah, its a typo. Time is surely not an issue. Instead of trying with a moving mesh, I varied a body force. Its giving good results even for small simulation time. Just that you wont see the mesh moving. but Its fairly sufficient for the analysis.
Hi Tamsu,
How did you use an oscillating body force in FLUENT? Did you use UDF or is there a better way to do so?

Thanks,
Venu

 November 24, 2021, 00:11 #9 Senior Member   Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34 to apply gravity you may use momentum source term to make it transient you may use transient profile or UDF and may be expression now (which should be checked) venu1591 likes this. __________________ best regards ****************************** press LIKE if this message was helpful

 Tags define_zone_motion, lateral excitation, sloshing, udf