Overlapping isovolume from two cases in CFD post
 

I have two cases which are identical to each other in geometry and fluid domain. The simulation is injecting a new fluid into a water domain from two different points. I want to see how this new fluid spreads. I have simulated and have got two result files. Now, separately, I have used isovolumes to check the injected fluid at different concentrations. For example, I have looked at regions with 50 percent new fluid concentration. This I am able to do separately. But I want to see the common region in the domain where the fluid in 50 percent for both the cases (injection points).
Can anybody help me find that out in CFD post?

I cannot see how to do this for volumes in CFD-Post. I would export it to a more sophisticated post processor like Ensight, Fieldview or Tecplot and try there. Paraview might be able to do it as well.

Can you point me towards some material where I can see how to do this on Ensight?

It is possible to calculate the difference between 2 cases. I.e., you can subtract one from the other. Not sure of this helps you, but it can bring new idea's and options that lead you to what you are looking for.......

Do you know how I can access variables from both cases while creating new expressions? For example, mass fraction of case1- mass fraction of case 2. The mass fraction variable is available by default but I am not sure how to differentiate it between the cases.

Also, by subtraction do you mean using the case comparison option or is there another way to do it?

Case comparison indeed. Other options, I don't know.