Numerical simulation of soft landing for clusters of cargo parachutes

In this paper, we present our methods for simulation of parachute fluid- structure interaction behavior and address some of the modeling challenges that are in- volved in this class of problems. We use methods which are based on interface-tracking techniques. Accordingly, we use the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation (1) for our flow computations and a Lagrangian finite element formulation for the parachute deformations (2), with advanced mesh update methods. Here, we focus on parachute soft landing applications, where payloads are retracted towards the parachute just prior to landing to reduce ground impact velocities. While soft landing retraction technology has been demonstrated for single parachutes and light cargos, lit- tle is known about the dynamics involved in retraction of large cargos with clusters of parachutes. Results are presented for simulations involving soft landings of cargo with a single parachute and with a cluster of two parachutes.