After simulation of single component multiphase flow (SCMP), i am trying to simulate multicomponent multiphase flow (MCMP) using the procedure described in the book “Lattice boltzmann modeling, an introduction for geoscientists and engineers”. It seems as if it contains insufficient data for simulation. like, I donot know that parameters i should provide as input(density initialization should be same as in SCMP by a random no. or by
directly providing distribution function)? what more input is needed? what should be value of G? how output would look like if plotted on TECPLOT 360 (like the output of SCMP was shown in the above mentioned book, so i compared my results with it)???
Please can anybody refer me the useful text for writung a fortran code for this problem…
I have been trying to reproduce the SCMP results of the Sukop books, but after few iterations the simulation converges to uniform densities at all sites. The same problem happens when I am doing 3D MCMP using Shan-Chen approach. Would you please send me your SCMP code, so that I can investigate the possible sources of error in my code?
I am also doing some part time research in LBM , especially Multi component/phase flow.
I,along with my mentor have been trying to write MCMP code, using Sukop’s book ,but to no avail.
Though We learnt certain things, which I want to share here:
Value of G: low value of G will make the two fluids miscible in one another, but if we take the value of G too large then numerical instabilities will occur. So start with a low G, then keep on increasing it till you stop getting stable soulutions.
2.You can initialize with a random value of density. Just remember that use this initial density to define your initial distribution functions.
But I also need your help. As I said, my code is not giving verifiable results . SO if you could share with me your code (SCMP & MCMP ), then That would go a long way in making me debug my own code. I have been working on this for months.
My email id is : vish.anand.iit@gmail.com
I know this reply is a year late but I’m currently trying to simulate a spray using LBM. I’ve written the code in Matlab, but I’m having a few problems with stability.
As soon as I increase the density ratio of the fluids (above say 3:1, ratio of density of fluid being injected to density of surrounding fluid) the program becomes numerically unstable.
The same thing happens on increasing the velocity of injected fluid, and on increasing the Greens function (G).
Can you please tell me the reason for this. I would greatly appreciate it if you could help me in this regard.
Just like Vikram, I am going to restart the old discussion, as I also share the more or less same pain as he has
I have been trying to use SC model for a moderate density ratio static bubble (just up to 10.). The problem is that setting G11 and G22 equal to zero and G12 to low values, would always result in a density ratio of not more than 2-3. For higher density ratios I have to set a large negative value for G11 (for the outer fluid) and an initial density ratio of minimum 2.0 which has the impact of having a non-pure fluid inside the bubble. Also this leads to inconsistent surface tension values for different bubble radii!!
Any help or idea is greatly appreciated in advance.
I’ve been looking over some stuff. So, the Shan Chen Equation of State(EOS) is pretty bad at handling large density ratios. The EOS controls your interaction potential function(psi).
The EOS needs to be changed if you want to handle large density ratios/gradients. From what I understand, this still won’t guarantee that it’ll work in every case.
There are other methods to handle large density gradients, one of them being the Lee and Lin method. Problem with that one is that you need to have an additional variable/matrix which computes your macroscopic variables like pressure and stuff alongside your particle distribution function (fIn, fOut, feq), which puts a lot of strain on your comp.
And it’s also based on the free energy method and not the pseudo-potential method.
I’m still learning, and the equations and concepts are really tough.
I still don’t understand how the Equation of State translates to the interaction potential.
Also, thanks for replying. Feels good to know that I’m not the only frustrated guy in the universe with this problem.
I’m studying on evaluaton of lattice boltzmann models on simulation of multiphase flows.
I simulated some problems by shan and chen method and now I want to simulate them by Free energy method.
I need to have an algorithm or a code to get more familiar with this method.
please help me, if you can.
Thank you.
I am relatively new to the topic and I am trying to use use LBM to simulate single phase and multiphase flow in complex geometry porous media. I am have been doing of reading and playing around with some general codes but I would appreciate some guidance from some anyone who already has codes for SCMP or MCMP.If you would be kind enough to, please share with me.
