Study on transient aerodynamic characteristics of parachute opening process

In the research of parachute,canopy inflationprocess modeling is one of the most complicated tasks.Ascanopy often experiences the largest deformations and loa-dings during a very short time,it is of great difficulty fortheoretical analysis and experimental measurements.In thispaper,aerodynamic equations and structural dynamics equa-tions were developed for describing parachute openingprocess,and an iterative coupling solving strategy incorpo-rating the above equations was proposed for a small-scale,flexible and flat-circular parachute.Then,analyses were car-ded out for canopy geometry,time-dependent pressure diffe-rence between the inside and outside of the canopy,transientvortex around the canopy and the flow field in the radial planeas a sequence in opening process.The mechanism of thecanopy shape development was explained from perspectiveof transient flow fields during the inflation process.Experi-ments of the parachute opening process were conducted in awind tunnel,in which instantaneous shape of the canopy wasmeasured by high velocity camera and the opening loadingwas measured by dynamometer balance.The theoretical pre-dictions were found in good agreement with the experimen-tal results,validating the proposed approach.This numericalmethod can improve the situation of strong dependence ofparachute research on wind tunnel tests,and is of signifi-cance to the understanding of the mechanics of parachuteinflation process.