Research on the inflation process of underwater parachute by numerical simulation and model test

Abstract

In order to meet the application requirements of the underwater parachute, the underwater inflation performance of a drag parachute is investigated based on numerical simulation and water tank test. A method for simulating the inflation process of underwater parachute based on Arbitrary Lagrangian Eulerian (ALE) method is proposed. The variation of axial force in the numerical simulation exhibits a similar trend to that observed in the model test, and the discrepancy of value between them is relatively insignificant. The purpose of this paper is to provide a basis for the evaluation and design of underwater parachutes for underwater applications. The effects of parameters such as permeability and flow velocity on the inflation performance are discussed in detail, and the analysis is carried out for parameters such as axial force and structural deformation. The results show that the high-stress zone and high-pressure intensity zone of the underwater parachute were found to be mainly concentrated in the center of the canopy and the joint. It can be observed both in model test and numerical simulation that, during the inflation process, vortexes are generated inside and outside the canopy. After the inflation shape of the canopy has stabilized under steady flow, lateral forces are generated on the parachute due to asymmetric vortex shedding, which cause the parachute to rotate around the axis.