NUMERICAL ANALYSIS OF REVERSE JET EFFECT ON THE AERODYNAMIC CHARACTERISTICS OF SSTO CONFIGURATION WITH AN AEROSPIKE NOZZLE IN LANDING PHASE

摘要

The mechanism of the flow interaction between a aerospike nozzle supersonic reverse jet and the subsonic freestream and its effect on the SSTO-rocket vehicle's aerodynamic characteristics is numerically investigated. At the lower pressure ratio, the freestream-induced recirculation is generated over the ramp and it leads to the lower pressure level in ramp area and the flow separation at the shoulder of the body is suppressed. As a result, the non-linear behaviour of the axial force coefficient against the pressure ratio is observed at the lower pressure condition. The leeside pressure varies in time due to the unsteady motion of the freestream-induced recirculation. The surface pressure in the ramp area varies in time due to the interaction between the motion of freestream-induced recirculation and the unsteadiness of inner shear layer. At the higher pressure ratio, the three dimensional vortical flow appears in front of the nozzle base and it leads to the large base pressure gradient. As a result, the aerodynamic characteristics of vehicle is statically unstable at the higher pressure ratio.