[Inderjeet Singh]

Hi everyone.. I am performing an 3-D analysis on sloshing in a tank. This has been done in ANSYS Fluent 18.2. For the practice, it is initially done using a rectangular tank model of dimensions 2mx1mx1m.

Let me explain the problem more clearly...

1. Structural Meshing is done in ANSYS meshing component and left face is marked as Moving wall.

2. VOF model On, 2 eularian phases , Air (Primary) and Water (Secondary)

3. Transient analysis, Time steps:
i) 0.01(s) x 50 steps ; max 45 iterations in each
ii) 0.001(s) x 100 steps ; max 45 iterations in each

4. 50% volume Patched to each Air and water (Using Volume Fraction).. after Initializing the case and then Patching the zones using Region cell marking.

5. UDF (as follows) for providing translatory motion to the tank corresponding to its velocity. The UDF is given to the full solid body. (Tried only moving wall, but it only moves the wall and not the whole tank, which stretches the tank size)

#include “udf.h”
#include “dynamesh_tools.h”
DEFINE_CG_MOTION(oscillate,dt,vel,omega,time,dtime )
{
Thread *t;
face_t f; /* define the variables */
t = DT_THREAD(dt);
begin_f_loop(f,t) /* loop over each face in the zone to create an array of data */
{
vel[0]=-2;
}
end_f_loop(f,t)
}


The whole procedure is mostly as explained in this video except top Outlet
BC and the UDF is applied on Solid body; (not left Moving wall)

-- https://www.youtube.com/watch?v=zttTAcO1S6I

__________________________________________________ ____________

So now where the problem comes;

Checked Mesh motion and the body moves; but after the solution in CFD-Post, There is no change observed in the volume fraction at any time. The contours showed unchanged at t=0s and final time.

Where i am making the mistake ? Is the UDF good enough to provide translatory motion to the closed tank in this case to see sloshing effect?

Below is the youtube link of simulation animation video -

https://www.youtube.com/watch?v=tNNfMZ2IXRg