A detailed analysis is presented of the nearly frozen, nonequilibrium supersonic expansion of a dissociated diatomic gas around a sharp, two dimensional corner, assuming an incoming stream in dissociation equilibrium. The analysis is based on a small perturbation technique in which small local departures from frozen flow near the corner are treated. The analysis is necessarily restricted in lateral extent but covers the entire angular range of the flow field and, therefore, brings out the nonlinear aspects of the nonequilibrium behavior. An exact analysis is presented (in similitude form for a diatomic gas) in which numerical procedures are required to effect the solution. However, in the exact solution, the expression for the atomic species mass fraction has been placed in closed form and, in conjunction with appropriate approximations, is used to determine the thermochemical field in an additional solution (applicable to hypersonic flow) which is approximate but entirely in closed form. Some numerical results for the first order nonequilibrium flow field are presented.

A method of characteristics for computing the supersonic, nonequilibrium flow of a reacting and relaxing gas was formulated. The theory was specialized to the ideal dissociating gas of Lighthill and the procedures coded on the IBM 7094. Complete listings of the FORTRAN programs are provided together with instructions as to their use. As examples of the computation techniques, the flows over a wedge and cone were computed and described in detail. For both the wedge and the cone, there developed downstream from the vertex an entropy layer near the wall, a relaxation layer near the shock where the quantities change rapidly, and a near equilibrium layer in between. It was found that it is important to keep the size of the mesh small enough to adequately represent the relaxation layer if satisfactory convergence to the equilibrium state is to be obtained. (Author).