Numerical Simulation of a Three-Dimensional Flexible Parachute System under Supersonic Conditions

Abstract

In the present study, the supersonic flow over a three-dimensional flexible parachute system is numerically simulated using a simple "immersed boundary method" together with the weak fluid-structure coupling scheme. The parachute system employed here consists of a capsule and a canopy. The mass-spring-damper model is applied to solve the structural dynamics of the flexible parachute system. The objective of this study is to analyze the effects of aerodynamic interaction such as wake/shock interaction on the dynamics of the canopy behavior, and clarify the performance of the flexible parachute system in terms of Mach number, the ratio of a capsule to a canopy diameter, and the trailing distance between the capsule and canopy. As a result, it is found that there are two key factors for the dynamics of the parachute system: one is the unsteady change in canopy shape and the other the aerodynamic interference between the capsule wake and the canopy shock. As the trailing distance increases reasonably, the area oscillation of the canopy shape is observed. However, by reducing the canopy size in the certain smaller trailing distance case, the canopy deformation is improved. Moreover, it is found that the free stream Mach number has a big impact on the canopy behavior in the smaller Mach number case, where the canopy undergoes smaller deformation, leading to a larger drag coefficient.

Parametric Study on Aerodynamic Interaction of Supersonic Parachute System

“…It was also found that the sting between the canopy and capsule has a rather small effect on the flow field and pressure distribution on the body surfaces, and the pulsation mechanism for the case without a sting is identical to that for the case with a sting. Xue et al [8] conducted the simulations of three-dimensional (3-D) flexible supersonic parachute system and found that there are two key factors for the dynamics of the parachute system: the unsteady change in canopy shape and the aerodynamic interference between the capsule wake and the canopy shock. Xue et al [9] performed the simulations of supersonic parachute system with canopy shrouds, and shock waves are generated upon the canopy shrouds, which exacerbate the flow field instability.…”

Numerical Study of Surface Pressure Fluctuation on Rigid Disk-Gap-Band-Type Supersonic Parachutes

“…However, their conditions were limited to very low speed (0.6-1.2 m∕s). Xue and Nakamura [9] and Xue et al [10,11] conducted a series of studies on supersonic parachutes. In Refs.…”

“…The effect of separation distance was surveyed in Ref. [9] for a flexible canopy. All these findings were of great importance, but they assumed laminar flows throughout their papers.…”