# 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: 4 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: 545 Rep Power: 12 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: 4
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: 545 Rep Power: 12 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: 4 Yup!! everything is great!

November 9, 2013, 10:24
sloshing
#6
New Member

Puneet
Join Date: Sep 2013
Posts: 13
Rep Power: 3
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

 Tags define_zone_motion, lateral excitation, sloshing, udf

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