I have a scenario
 

Hi guys,

I have an interesting cfd modeling problem which is not mine officially yet, but I need some ideas/inputs before I actually do this.

Anyway here is the problem.

We have 2 liquid, say A and B. Liquid A travels a fairly long tube at given velocity, Re, etc. At time zero we start switching the liquid A with liquid B at the source. Liquid A and Liquid B are miscible, so at some point a long the tube we will have

--------------------------------------------------- Liquid B---+------Mixing Zone----+---Liquid A ----> ---------------------------------------------------

Provided adequate information, I want to model how this "Mixing Zone" forms a lon the tube and thus I need the general input from you guys on how to set up the problem in CFD. I need to know how "hard" it is to set up this kind of problem.

Thank you guys

Pandu

Re: I have a scenario
 

Hi Pandu,

This is a relatively easy problem to setup. Starting from a converged steady state solution (representing time 0 s), you will run a transient simulation (second order transient preferably), with a transient boundary condition (or a new b.c. if it is a step change from A to B). Exaclty how to do this will depend on the code you are running.

Regards, Robin