# vof fluid sloshing in tank with rolling tank

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 August 22, 2016, 02:44 vof fluid sloshing in tank with rolling tank #1 Member   naveen kumar s Join Date: Aug 2016 Location: india, bengalore Posts: 51 Rep Power: 8 hello, I have simulated sloshing technique in fluid tank in cfx ansys 14, but my problem is i have used expression for angular velocity of using sinusoidal (expression name is "amp" and its image is in attachment), this expression i have put in domain motion , the rolling of tank is 6 degree but in expression is my equation (angle in radiens*omega in (rad/sec)*sin(omega*t)) is right , i have multiplied omega with roll angle in radians , just see my expression , can i multiply angle in radians to omega (which is frequency). and below domain motion there is alternate rotation model what it does alternate motion , please give is there any other expression can give for fluid motion. can i give motion in initiation, u,v,w is there please help me thank you Last edited by navi; August 22, 2016 at 03:24. Reason: i guess image dind uploaded so typed an equation

 August 22, 2016, 06:49 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,327 Rep Power: 138 I do not understand your question. Can you state your question again?

 August 23, 2016, 00:35 #3 Member   naveen kumar s Join Date: Aug 2016 Location: india, bengalore Posts: 51 Rep Power: 8 for tank motion i have to give expression and my tank motion is rolling in degrees , it is 6 degree , and i have given expression as (6*(pi/180))*omega*sin(omega*t) omega is in rad/sec in above equation i have multiplied omega * (rolling angle in radians) is my equation is right for tank simulation i am giving this expression in outline tree default domiain> basic setting > domain motion > rotating > angular velocity in same dialog box, there is alternate rotation model, what this alternate rotation model does exactly

 August 23, 2016, 06:03 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,327 Rep Power: 138 So you are using rotating frames of reference to model an oscillating rotation? Be aware that rotating frames of reference assumes constant domain velocity so the angular accelerations will not be accounted for. It is up to you to determine whether that is important or not. If you model this using moving mesh it will include the full motion equations but the simulation will be considerably slower.

 August 23, 2016, 06:12 #5 Member   naveen kumar s Join Date: Aug 2016 Location: india, bengalore Posts: 51 Rep Power: 8 how can i apply moving mesh for 3d tank, in tutorials there are only for 2d and when i try doing it by understanding 2d and applying same for 3d ,i need to give mass, moment of inertia , all this i how can i feed correctly

 August 23, 2016, 06:48 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,327 Rep Power: 138 If you are using mass and moments of inertia then you are using the rigid body solver. I think you need to go back to basics and make sure you are modelling the correct physics. Is the motion known in advance or is it coupled to the the fluid motion? Does the tank deform at all? Please show an image of the tank motion.

August 24, 2016, 00:54
#7
Member

naveen kumar s
Join Date: Aug 2016
Location: india, bengalore
Posts: 51
Rep Power: 8
i have attached image, for this type simulation, i have alone gone through basics but its lil bit difficult so getting lot of doubt
Attached Images
 Capture.jpg (79.2 KB, 41 views) expresions.JPG (25.7 KB, 26 views)

 June 2, 2018, 00:51 sloshing and ship motion #8 New Member   Join Date: Nov 2016 Posts: 16 Rep Power: 8 how to get result of sloshing pressure on tank walls ?

 June 2, 2018, 08:04 #9 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,327 Rep Power: 138 * Put a monitor point on the surface recording the pressure. Then you will get a time history of pressure at that point in Solver Manager. * Integrate the pressure over the surface to get a force using the force function. Then put that CEL function in as a monitor point and you will have a time history in solver manager. * You can also do this in post-processing for any time steps you saved transient results files for. kites likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 Tags expression, initiation, sinosoidal, sloshing, vof