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-   -   level set for multi-fluids system? (http://www.cfd-online.com/Forums/main/2387-level-set-multi-fluids-system.html)

 Pei-Ying Hsieh July 19, 2000 15:27

level set for multi-fluids system?

Hi,

I just started reading level set method. Before I invest a lot of time learning the level set method, it will be appreciated if anyone can help me with this question.

The problem I am working on involves several types of fluids, i,e, oil, liquids, and air, in the computational domain. Can level set be applied to multi-fluids system? The papers I have obtained so far only applied the level set to 2-phase (2-fluid) flow. Thanks!

 Kalyan July 19, 2000 16:42

Re: level set for multi-fluids system?

You cannot use a single field equation to track more than one type of interface, i.e. the level set method is based on binary representation of the material.

However, there is one approach that can perhaps be used. I have not had the time to look at this idea more carefully nor have I seen it implemented elsewhere. Here is the basic idea. Define a field variable for each of the phases (air, water, oil etc.).

Air : G1

Oil : G2

Water : G3

Pick a unique level surface of G1 (say G1=0.5) to represent the surface that separates air and other material.

G1 < 0.5 ===> presence of air

G1 > 0.5 ===> no air (we can have oil "or" water).

Thus we have binary representation for each component of the fluid. So for a three component system, you have three field equations that need to solved.

G1 = 0.5 surface separates regions with and without air,

G2 = 0.5 surface separates regions with and without oil,

G3 = 0.5 surface separates regions with and without water.

If you have obtain the equations for the the field variables, you have a solution methodology.

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