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vof fluid sloshing in tank with rolling tank

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Old   August 22, 2016, 02:44
Default vof fluid sloshing in tank with rolling tank
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naveen kumar s
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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
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Old   August 22, 2016, 06:49
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I do not understand your question. Can you state your question again?
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Old   August 23, 2016, 00:35
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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
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Old   August 23, 2016, 06:03
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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.
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Old   August 23, 2016, 06:12
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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
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Old   August 23, 2016, 06:48
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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.
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Old   August 24, 2016, 00:54
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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
File Type: jpg Capture.jpg (79.2 KB, 42 views)
File Type: jpg expresions.JPG (25.7 KB, 27 views)
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Old   June 2, 2018, 00:51
Default sloshing and ship motion
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how to get result of sloshing pressure on tank walls
?
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Old   June 2, 2018, 08:04
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* 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.
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