CFD Online Logo CFD Online URL
Home > Forums > FLUENT


Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   September 6, 2007, 22:55
Default Sloshing
Posts: n/a
I am doing a sloshing problem. I define my boundary conditions as functions of time and don't have fluid draining from my tank(boundary condition is wall).

-The solver must be unsteady (1st order implicit)

-the multiphase model is obviously VOF. Turn on the implicit body force option

-the viscous model is laminar

-set the phases. The primary phase should be the lighter

-on the operating conditions panel, enable gravity and specify the operating density as the one of the lighter phase.

-on the boundary conditions panel, turn on the source terms and use my momentum source

-keep my URFs quite big (0.6 and 0.8 for pressure and momentum respectively, 1 for the other parameters)

-discretization schemes: BODY FORCE WEIGHTED for pressure, PISO for pressure velocity coupling (skewness correction=1, neighbour correction=1, turn on the skewness neighbor coupling), FIRST ORDER UPWIND for momentum.

-once I initialize the flow field to create an adaption register for patching the initial fluid location (adapt>region, then patch the liquid volume fraction solve>initialise>patch, select the volume fraction of the liquid as 1)

-keep my time step quite small(0.001).

This is my UDF

#include "udf.h"

double AlnrX;

DEFINE_ADJUST(Accl, domain) { double t;

t = RP_Get_Real("flow-time");

AlnrX = -0.0363*sin(1.1*t);

printf("time = %f\n",t); printf("accel = %f\n",AlnrX);


DEFINE_SOURCE(xmom_source, cell, thread, dS, eqn) { double pos[ND_ND]; double rho; double source;


rho = C_R(cell,thread);

dS[eqn] = 0.0; source = AlnrX *rho;

return source; }

But my calculation is wrong comparing with experiment. Please tall me what is wrong on my setting.

Thank you very much!

  Reply With Quote

Old   September 7, 2007, 06:11
Default Re: Sloshing
Posts: n/a
How is it wrong?

Grid and timestep independance?

Higher order spatial and temporal discretisation?

Start with a simple dam breaking validation to check your numerics.
  Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Force Window and sloshing mass satellite_control FLOW-3D 0 October 6, 2011 09:04
Linear analytical solution oto the 2D free sloshing water surface elevation bearcat Main CFD Forum 7 August 5, 2011 20:13
Calculating Sloshing mass in a cylinder satellite_control FLOW-3D 0 June 20, 2011 05:34
Sloshing frequency determination alastormoody11 STAR-CCM+ 0 January 20, 2011 23:40
Udf for sloshing problem D.Martelli Fluent UDF and Scheme Programming 0 December 9, 2009 12:21

All times are GMT -4. The time now is 11:37.