Numerical Simulation of Flow Field around an Inflatable Reentry Vehicle during a Demonstration Flight

Abstract

A flight experiment of an inflatable reentry vehicle, which equips a thin membrane aeroshell deployed by an inflatable torus structure, was performed by a JAXA S-310-41 sounding rocket. The vehicle successfully demonstrated deceleration at a high altitude. During the reentry flight, position, velocity and acceleration of the vehicle were obtained by the global positioning system. Moreover, drag coefficient history was evaluated by the acceleration of vehicle with atmospheric density and temperature by a global reference atmospheric model. Experimental drag coefficient was almost constant value of 1.5 in supersonic region, while that decreased to 1.0 in subsonic region. At transonic region, steep decrease of the drag coefficient was confirmed. To study detailed aerodynamics for the reentry vehicle, flow field simulations were conducted with computational fluid dynamics techniques. Aerodynamic force acting on the vehicle was investigated with the measured data throughout the supersonic and subsonic regions. In the flow field simulation, it was indicated that the computed result of drag coefficient shows reasonable agreement with the experimental one. In addition, it was clarified that compressible effect in front of the vehicle remarkably appears in supersonic region, and a feature of vortex ring at the rear of the vehicle is formed in subsonic region.