Fluid–Structure Interaction Dynamic Response of Rocket Fairing in Falling Phase

Abstract

A method based on fluid–structure coupling is used in this study to calculate the response of a rocket fairing as it is falling. Some cases of vibration divergence of the fairing were found, and the influence of some specific factors was analyzed. The aerodynamic forces are calculated by using computational fluid dynamics (CFD) software and the structural responses by the modal-superposition method. The data are then subjected to modal interpolation in the CFD solver for the next cycle of calculation. The dynamic pressure, Mach number, and angle of attack are fixed in this process. Given that the fairing has a fixed attitude during falling, its rotation is ignored in calculations for the simulation. The results are then used to propose a framework for the fluid–structure coupling-based analysis of a non-streamlined structure. The mechanism of the fairing is discussed based on this method, and the effects of the settings of the solver, Mach number, dynamic pressure, and structural stiffness on it are investigated. Dangerous and safe regions are identified as the fairing falls back to the ground. Three methods are then provided based on the above analysis to prevent damage to the fairing as it falls to ground, such as increasing structure rigidity, attitude control, and opening the parachute at high altitude. A comprehensive method was used to suppress the vibration of the fairing during the descent, which was proven to be effective.