Study on transient aerodynamic characteristics of parachute opening process

In the research of parachute, canopy inflation process modeling is one of the most complicated tasks. As canopy often experiences the largest deformations and loadings during a very short time, it is of great difficulty for theoretical analysis and experimental measurements. In this paper, aerodynamic equations and structural dynamics equations were developed for describing parachute opening process, and an iterative coupling solving strategy incorporating the above equations was proposed for a small-scale, flexible and flat-circular parachute. Then, analyses were carried out for canopy geometry, time-dependent pressure difference between the inside and outside of the canopy, transient vortex around the canopy and the flow field in the radial plane as a sequence in opening process. The mechanism of the canopy shape development was explained from perspective of transient flow fields during the inflation process. Experiments of the parachute opening process were conducted in a wind tunnel, in which instantaneous shape of the canopy was measured by high velocity camera and the opening loading was measured by dynamometer balance. The theoretical predictions were found in good agreement with the experimental results, validating the proposed approach. This numerical method can improve the situation of strong dependence of parachute research on wind tunnel tests, and is of significance to the understanding of the mechanics of parachute inflation process. The project supported by the National Natural Science Foundation of China (10377006). The English text was polished by Yunming Chen.