The numerical and experimental studies of pressure pulsations on the surface of the ascent unit with manned transport spacecraft in the launch phase

The results of the numerical and experimental study of the turbulent flow over the re-entry cone with manned transport spacecraft and the emergency rescue system in the launch phase are presented. The main task of these studies is to determine the amplitude-frequency characteristics of pressure pulsations on the surface of the return vehicle. A combined two-stage scale-resolving approach to turbulence representation developed for this purpose is described in some detail, and the results of its verification are presented based on the comparison of the predicted unsteady surface pressure with measurements of pressure pulsations made for the 20 times reduced model configuration in the wind tunnel of TsAGI Т-128. The analysis of the results of simulations of the full-scale configuration at subsonic, transonic and supersonic speeds of flight suggests that in the launch phase the re-entry cone surface experiences strong dynamic loads (at Mach number М = 1.5 intensity of the surface pressure pulsations reaches 175 dB). It is also shown that a significant (up to 7 dB) contribution to these loads is due to turbulent vortex structures populating wakes of nozzles of the emergency rescue unit.