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-   -   How to estimation the dsmcFoam has get steady-state condition? (http://www.cfd-online.com/Forums/openfoam/83361-how-estimation-dsmcfoam-has-get-steady-state-condition.html)

luffy0503 December 24, 2010 12:56

How to estimation the dsmcFoam has get steady-state condition?
 
Dear foamers,

I used dsmcFoam to simulate hypersonic flow. The example of estimation of steady-state conditions in the paper "T.J. Scanlon, E. Roohi, C. White, M. Darbandi, J.M. Reese. An open source, parallel DSMC code for rarefied gas flows in arbitrary geometries. Computers & Fluids 39 (2010) 2078-2089 ". It used the total number of DSMC particles in the system to estimate the iteration achieved steady-state that show in Fig.3 on the paper.

We can see the total number of DSMC particles in the "log.dsmcFoam" file of each time iterate. How to plot the graph that X axis is iterations, Y axis is the number of DSMC particles by captured the partilces data from the "log.dsmcFoam" file? Then estimate the iterations achieved steady-state condition.

Paul_Re November 1, 2011 06:49

"The full DSMC simulation is considered to have reached steady-state when the total number of simulation particles no longer varies appreciably."

A hybrid particle-continuum method applied to shock waves, Journal of Computational Physics, Volume 215, Issue 2, 1 July 2006, Pages 402-416

I think it is the typical requirement for an steady-state.

My value out of log.dsmcFoam is

Number of dsmc particles = 1272

So i think one should consider this value, or? Is this value not changing you may have something like an steady-state.

But i am not sure how to visualize in paraFoam these values (iterations vs no of particles). There are some statistical filters ... these could be used ...

But I think you have to collect them manually out of log.dsmcFoam ... ?

b.r., p


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