Rotational relaxation model for nitrogen and its application in free jet expansion problem

This paper studies a rotational relaxation process in nitrogen. A series of more than 200 x 10(6) classical trajectory calculations (CTCs) of collisions of nitrogen molecules were carried out. Based on the CTC results, a collision model accounting for rotational relaxation was proposed and used for three-dimensional event-driven molecular dynamics simulation of a free jet expansion. It was shown that the collision model parameterized by the CTCs can produce results in good agreement with the existing experimental measurements.