About some comment

[gialbokhary]

Hello every one around here!
Please, refer to the statement "IF (IFX.GT.0) A=0.5*A" at line 498 of program DSMC1U.FOR and particularly its comment "For cylindrical and spherical flows, molecules are generated in pairs such that there is zero initial momentum in the axial direction" at line 499 & 500. Actually, I'm not able to understand the justification on above comment from the physical point of view! Hope if there is any one can help me? Not that is not programming matter, it is about physics.

[schuberm]

Bird walks through his programs in his book: http://www.amazon.com/Molecular-Dynamics-Simulation-Engineering-Science/dp/0198561954 . Highly recommended.

[gialbokhary]

thanks, i'm already have a copy from this book and it is the main material that i have used to understand dsmc procedure but still there are some view problems remain and this particular problem haven't mentioned in his book. anyway thank you for your suggestion.