Helo,

I still wonder if I am doing something wrong or the computations are really so demanding and time consuming. Can you present here some details about some of your experiences?

I start with this:

Platform: Win2003, AMD64 3200, 2GB RAM dual PC400

Problem:

- unsteady simulation,

- rushton turbine (240 rpm) in a 20x20cm tank with 4 baffles,

- sliding mesh,

- VOF (air-water),

- k-epsilon,

- PISO,

- pressure: Body Force Weighted,

- under-relaxation factors - all 0.1,

- about 31000 cells of mesh.

Time: 1 second is computed in about 10 hours

I think its quite long, maybe I make some mistake?

Your settings sound quite good. Typical VOF unsteady application. Anyway your computational time is actually quite large (never did a serious benchmark, but it takes me approximately the same time, 1 second flow time in about 8 hours, for 400k cells model on a Linux machine).

How long does it take you 1 iteration? Which is your time step? How many iterations are required for a time step?

Reading back your post: maybe you're URFs are too low...try something like:

-pressure: 0.6

-momentum: 0.8

-others: 1

Hope this can help

Edi.

1- Check the swap area 2- Check the performance of the microprocessor (Right click on the bottom of the screen, select the task manager then the performance tab)

Swap file is probably not used as system disposes 2GB RAM memory and fluent takes about 150MB also processor works at 99%.

I found the problem existing rather in simulation settings than in system settings.

I changed the under relaxation factors and simulation speed increased 5 times - quite good. I set the urfs very rigorously because at the initial stage the integration bacame unstable - so it's worth to "loose" the urfs a little after the simulation has already passed that troublesome initial stage.

reagrds Maciej