CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Multiphase modelling using Fluent VOF: Solver settings

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

LinkBack Thread Tools Search this Thread Display Modes
Old   February 22, 2013, 06:29
Default Multiphase modelling using Fluent VOF: Solver settings
New Member
Join Date: Jan 2013
Location: India
Posts: 20
Rep Power: 13
akash is on a distinguished road

I'm trying to simulate shape oscillations of a drop in fluid. The two fluids I'm using are defined using user-defined properties to get required Reynolds number and Webers number. Its is a transient 2D problem where the shape of the drop, initially perturbed changes w.r.t. time to attain circular shape due to surface tension. But due to the inertia it starts oscillating and the amplitude decays due to the presence of viscosity.

I need to monitor the frequency and the amplitude of the oscillations. And I'm not getting the required result. The results are severely off from the analytical solution. I guess I'm setting some solver parameter wrongly. Please help me identify and also any suggestions are welcome.

I'm mentioning all the settings I'm using, step by step. (I'm using Ansys 14)

1) Import the grid, scale it to 'cm'. Set units to 'cgs'. Adapt a region (circular-0.75cm).
2)Set 'Pressure based' and 'Transient' solver. (Pressure based because both the fluids are incompressible)
3)Select 'VOF model' in multiphase model and use the default settings. (Explicit VOF, because I need time accurate solution)
4)Viscous model is 'Laminar'.
5)In materials I copy my user defined materials.
6)Set the primary and secondary phase, and also set the surface tension in the 'interaction' option.
7)Set the boundary and operating conditions.
8)Solution methods - Pressure-velocity coupling: PISO
Spatial Descritization- Gradient:Least Squares cell based
Pressure: PRESTO!
Momentum: Second order upwind
Volume Fraction: Geo-reconstruct
Transient Formulation- First order Implicit
9)Initialize solution from all zones.
10)Fixed time step. Time step of 0.001. Run simulation for 10000 time steps. Max iter/step-50.
The things which I have not mentioned, it means I have used the default settings.

Actually the solution converges at each time step. Also the solution is quite physically feasible. But the frequency of oscillation is not matching at all.

Can anyone let me know where I'm going wrong.
akash is offline   Reply With Quote


fluent, multiphase, vof modeling

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Modelling falling solid sphere using interFoam VOF model eelcovv OpenFOAM Running, Solving & CFD 6 August 7, 2021 21:52
thobois class engineTopoChangerMesh error Peter_600 OpenFOAM 4 August 2, 2014 09:52
Solver Settings for transient flow past circular cylinders mahi007 FLUENT 10 March 20, 2012 04:49
fluent multiphase modelling thinktank FLUENT 0 November 28, 2009 13:41
Problem with VOF in fluent ash-khan FLUENT 2 November 3, 2009 02:00

All times are GMT -4. The time now is 02:48.