Stable Lateral-Force in Distributed-Suspension Cruciform Parachutes: Mechanism and Parametric Effects

Periodic coning and spin motions limit the ability of conventional cruciform parachutes to generate stable lateral aerodynamic forces for precision airdrop applications. This paper proposes an aerodynamic control strategy based on a distributed suspension-line configuration for a cruciform parachute and investigates its lateral-force-generation mechanism and the effects of key geometric parameters on aerodynamic force using an arbitrary Lagrangian–Eulerian (ALE) method. In the configuration, the suspension lines, instead of converging to a single point, are attached at circumferentially distributed locations on a disk, which mitigates coning motion and enables sustained lateral-force generation. The results show that asymmetric shortening of the control lines induces a sustained canopy deflection and generates a quasi-steady lateral aerodynamic force by breaking the wake symmetry. Flowfield analysis indicates that the lateral force is associated with the downstream shift of flow-separation point along canopy arms, a redistribution of vortical structures near the canopy, and the formation of a dominant asymmetric leeward vortex. Parametric analyses show that increasing the disk diameter improves dynamic stability, especially at low freestream velocities. Regime maps are constructed to identify the parameter ranges associated with normal inflation and stable lateral-force generation. These results provide physical insight and design guidance for controllable cruciform parachutes.