Which dynamics, lattice and data processor for simple advection?

Palabos General
#1

Hi,

I implemented advection and diffusion with the shan chen model. Now I want to try how it behaves, if I completely leave out the diffusion.

Can I do so with Shan/Chen (minimal changes to my code), or do I have to switch the model?

Is there an easier way to do simple advection?

Best wishes,
Arne

#2

Hi Arne,

I guess you can’t avoid the diffusion - this stuff exactly forms your interface. That’s why it’s called diffusion interface. Moreover, to specify diffusion to be equal zero you need to put omega=1/2 which is explicitly unstable.

Probably I’m not right,
Alex

#3

I now solved the issue by simply not using two fluids: I only need advection, so just saving and importing the velocity field proved to be easier…

I now let particles move step by step on the velocity field. It’s not perfect, but it allows me to directly use the velocity field more easily, which opens up some new options for me.

What I do to get a 1024x1024x1024 velocity field without filling up my disk (or having to code compression :wink: ):

mkfifo velocityFieldOut.dat
cat velocityFieldOut.dat | bzip2 --fast > velocityFieldOut_arbitrary_precision.dat.bz2

Now just write to velocityFieldOut.dat.

(only works in *nix systems)