Hello everybody. My CFD code is about a fluid coming in a closed area.This means that there is ofcourse an inlet,but NO outlet.The flow is compressible.The boundary conditions in the inlet is prescribed velocity,but is there something missing? Thank you

Subsonic hard inflows allow you to specify all components of the velocity, the temperature, and the species mass fractions. This leaves one left for the Navier-Stokes Equations. The simplist thing to do for the last BC is to specify

(n dot tau dot n)

where n is the boundary normal and tau is the viscous stress tensor, or

(n dot [n dot Grad]tau dot n)

There is an alternative procedure that was derived for nonreflecting approaches that tries to specify the density in a self-consistent manner. It is described here for simple gases (not gas mixtures)

http://scholar.google.com/scholar?hl=en&lr=&q=poinsot+lele+Boundary+conditions+direct+simulations+of+co mpressible+viscous+flows&btnG=Search

http://adsabs.harvard.edu/cgi-bin/np...4P&db_key=INST