Computer simulation of the flow and the relative motion of the reentry vehicle and the parachute compartment hatch cover in the course of their separation during descent

The paper addresses the simultaneous solution of the problems of determining aerodynamic properties and relative motion of the re-entry vehicle and the parachute container hatch door during their separation, performed by TESIS and RSC Energia using computer (math) simulations based on the FlowVision software package. The problem was solved in connection with the reentry vehicle of the advanced transportation vehicle that is under development by the RSC Energia. Studied was the effect on the separation process of the initial values of kinematic parameters of the reentry vehicle (flight velocity and altitude, angle of attack and roll, angular rates), forces of the cover pushers, drogue parachute lanyard and other factors. Critical parameter values were identified at which collisions are possible between the reentry vehicle and the parachute container hatch cover. Recommendations are provided for sizing and selecting the best structure of the computational grid, as well as the time integration step required for obtaining a satisfactory convergence when solving this kind of problems. Provided for some of the regimes that have been studied are time profiles for coefficients of aerodynamic forces and moments of the reentry vehicle and the parachute container hatch cover, relative coordinates of the center of mass of the hatch cover in the course of separation and its motion record, allowing to trace back the effects of the initial values of the variable parameters on the motion trajectory. It was established that instability of motion in the vicinity of the reentry vehicle, characteristic of these regimes of flow (М ∞ ~ 0.6...0.8; α = 10...30°), and the asymmetry of flow that is produced in the process, as well as the initial angular rate of the spacecraft about its long axis produce a lateral force, roll and yaw moments and, as a result, spatial motion of the parachute container hatch cover with the motion trajectory leaving the plane of the angle of attack of the reentry vehicle.