Understanding multiphase modeling (VOF) - Part 1

"Understanding multiphase modeling (VOF)" - Part 1

This material is published under the creative commons license CC BY-NC-SA (Attribution-NonCommercial-ShareAlike). If you plan to use it, please acknowledge it.

This video contains auxiliary material for students at the Johannes Kepler University in Linz, Austria. Students from other universities are welcome to use it for their learning purposes.

Thanks to Gavin Tabor from the University of Exeter for his input.

This series is based upon CFD tutorials created at the Vienna University of Technology in a cooparation with Bahram Haddadi, Christian Jordan and Michael Harasek and further improved at the Johannes Kepler University in Linz, Austria.

The used OpenFOAM version was precompiled by Andras Horvath from Rheologic GmbH, you can download it here:

[edwardvasquezmorales]

Bien Jozsef, felicitaciones y gracias. Un saludo desde Perú.

[andremartins]

Dear József, sincere thanks for sharing this video with us! I'm very excited about learning OpenFoam and your videos are awesome, best regards from Brazil!

[jayangasamarasinghe]

Thank you very much for the descriptive tutorial. Could you please let us know how to change/ generate Alpha.water file.

[gordonfreeman]

Thank you very much for the amazing tutorial videos!!

I just wanted to know how do we interpret the alpha values between 0 and 1. If the alpha value is say 0.05 at a location, does it mean that there is mist present there? As in is the simulation predicting there are small liquid droplets in the vapor at that location? Or do we interpret it as approximately 0 hence fully vapor?

[joshmccraney]

Kind of a general question here, but is there a way to run interFoam until it reaches steady state and then run setFields again? I'll happily donate if you have a technique (I have before and will again).

[shehabsalem-hobx]

Thank you very much for the descriptive tutorial. Could you please let us know how to change from Newtonian to non-Newtonian?

[zengchensun]

Hi sir. What is the 2S means in momentum equation?

[saketh]

I have a problem in loading alpha.water values in paraview. I am seeing only 0 assigned to all points(including the box). But inside the file i see that 1 being assigned to points in the box and 0 to remaining points outside the box. I tried twice with setfields but it didnt work. Am I doing something wrong?

[sumitzanje]

How to calculate the void fraction for a pipe flow over time? Basically I want to plot "Time Vs. Void fraction" for a pipe carrying bubbly flow. I'm focusing on one particular section and want to determine void fraction in that section and how it changes over the time as bubbly flow is passing through it.

[sandipgewali]

After running the setFields utility, nano/gedit can't open the 0/alpha.water file. Despite that, I can see the water column in paraview. Still, why can not the nano/gedit read the 0/alpha.water file ?? It can't display the list of values of alphas for various cells. Instead the list seems cryptic with just "@" signs over there. The rest of the boundary conditions stay the same.

[nikhilbhamare]

Yes sir yes. Magical water column.
I really like your videos. 👌🏻👍🏻😄

[letstravelsomewhere]

I need to design Pipeline inspection Gauge for my final year - am i in the right track ?

[prakashachandrasahoo]

Dear sir, how to calculate impact velocity of water droplet impacting on solid surface in Ansys fluent and what is range value of that droplet velocity?

[prakashachandrasahoo]

What is the procedure to calculate that impact velocity of droplet in numerical method?

[samahbendada]

Hello.
I am new at Open Foam.
I tried to run this system and i did all of your steps, but I dont know why the alpha is zero at all time steps.
I would appreciate your help in this problem.

[ابوعائشة-جم]

Can you help me please to simulate bubble column?

[DaylightDigital]

In the final VOF equation, what is u_r? What velocity is being referenced here?

[DpointW]

Hi,
I have a short and probably quite simple question about the presentation of the results of interFoam in Paraview.
So there are two phases, air and water. To view only the water in Paraview, I use the clip function in conjunction with scalar and set the alpha value to 0.5. What I haven't quite understood yet is what this value stands for? Does this mean that all cells containing at least 50% water are displayed?
In simulations with a finer grid, areas were also displayed in which there was no water according to the coarser grid.
Or is this a clear indication that my grid is too coarse?

[avinashkumarverma]

after executing setFields command it is showing FOAM warning and no list of alpha values is appearing as you have shown in this video. What might the problem? Can you please explain? I have followed this tutorial of yours step by step.

[haivandang]

I can do most of the video. but in final stage, after coding foam.foam. I cannot open foam.foam in paraview. Please let me know. Thank you for your support