Simulation of impact of the wakes of emergency rescue unit’s nozzles on the surface of a manned spacecraft

Results are presented of numerical simulations of impact of the wakes of emergency rescue unit’s nozzles on the surface of a manned spacecraft. The computations are carried out in the framework of a two-stage RANS-LES methodology proposed and validated by the authors earlier. Within this methodology, the wall-modeled LES (WMLES) is represented by a well-known scale-resolving approach IDDES. In the present work, this methodology is enhanced by including in the WMLES-subdomain the first row of the emergency rescue unit's nozzles and by covering the entire ($360^\circ$) azimuthal domain. This allows increasing accuracy of the simulations due to a more correct representation of the wakes of these nozzles and also addressing the effect of non-zero angle of attack. Analysis is performed of the effect of the flight Mach number on the amplitude and spectral characteristics of the pressure fluctuations on the spacecraft surface, including their alteration at the sonic barrier. Other than that, at the transonic Mach number value of $\mathrm{M}_\infty = 0.95$, the effects are analyzed of a non-zero angle of attack and of relative azimuthal location of the first and the second rows of nozzles of the recue unit.