water sloshing in oscillating tank (problem using udf Define_ZONE_MOTION)
 

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 <udf.h>
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?

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.

You said it first! I was just going to suggest that. So is everything fine now?

Yup!! everything is great! :)

sloshing
 

sir i m facing same problems...how did u rectify those..plz help me out

Sumit,

Can you please let me know how to go about solving this problem

Thanks,Samwize

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

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)