A rarefied gas flow into vacuum through a tube of finite length is investigated over the whole
range of gas rarefaction by the direct simulation Monte Carlo method. The nonequilibrium
effects at the inlet and outlet of the tube have been considered by including in the
computational domain large volumes of the upstream and downstream reservoirs. Results
for the dimensionless flow rate and for the flow field are presented for a wide range of the
gas rarefaction and for various values of the length to radius ratio in the range from 0 to 10 …