DIRECT SIMULATION OF DIATOMIC GASES USING THE GENERALIZED HARD-SPHEREMODEL

The generalized hard sphere model that incorporates the effects of att raction and repulsion is examined. First, the model is used to study s imple adiabatic heat baths. Then, it is used to predict now measuremen ts in tests involving extremely low freestream temperatures. For the t wo cases considered, a Mach 26 nitrogen shock and a Mach 20 nitrogen f low over a flat plate, only rotational excitation is deemed important, and appropriate modifications for the Borgnakke-Larsen procedure are developed. In general, for the cases considered, the present model sho wed a modest improvement over the variable hard sphere model.