Abstract
It is well known that the flow-field over blunt and pointed bodies is sensitive to the non-equilibrium phenomena characteristic of high enthalpy hypersonic flows. Till date, most experiments and modelling were related to flows essentially dominated by the dissociation rate. However, in practical cases of a re-entry low density flow, the aerodynamic quantities such as the shock shape and location may also be strongly influenced by vibrational relaxation coupled with dissociation and chemical reactions. Thus, the flow about various bodies such as spheres, hemisphere–cylinders and cones is recomputed using a chemical model recently proposed by the authors and by taking into account the coupling between the vibrational relaxation and the chemical kinetics. Then, the computed shock shapes in air flow are compared to recent experimental results obtained in a ballistic range for flight velocities between 2,500 and 4,000 m/s, and in a shock tunnel for enthalpies close to 5 and 10 MJ/kg. The computed density field around hemispherical bodies is also compared to the experimental one. A good agreement, within 5%, between computed and measured results is observed. A few comparisons are also proposed with the results obtained with another well-known (empirical) model. A comparison is also made between the flow quantities along the stagnation line obtained over cylindrical and spherical bodies using the present model and those coming from a quasi-one-dimensional model recently developed, showing also a satisfactory agreement.
Published Version
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