Transonic/supersonic aerodynamic characteristics and fluid-structure interaction mechanism of flexible parachutes for planetary exploration
Further missions of China's planetary exploration projects to the Venus,the Jupiter and others have been initiated,and the key technical research is underway.However,these planets have significantly different atmospheric environments from those of the Earth and the Mars,with dense atmospheres and higher atmospheric pressures.Pre-vious successful planetary explorations reveal that the aerodynamic deceleration process in such complex planetary at-mospheric environments requires multi-stage parachutes and transonic/supersonic conditions for parachute opening and operation.Meanwhile,the nominal diameter of the first stage guide parachute is significantly smaller than that of the main parachute and the forebody diameter.With few related research reports,the fluid structure interaction mechanism and the aerodynamic characteristics between two-stage parachutes of different sizes and the forebody are still unclear.In this research,based on conical ribbon parachutes and disk-band-gap parachutes suitable for dense at-mospheric planetary exploration missions,the fluid structure interaction mechanism of flexible parachutes in different planetary atmospheric environments is numerically studied using the immersion boundary method,and the aerody-namic characteristics with different freestream Mach numbers,canopy types,atmospheric components,and param-eter to diameter ratios are investigated.Results show that in the atmospheric environment of the Titan,the conical rib-bon canopy(with a diameter ratio of 0.3)steadily descends at transonic speeds,and the projected area of the canopy increases over time.The drag coefficient reaches its maximum at Mach number 1.5,while its fluctuation monotoni-cally increases with the increase of the Mach number.In addition,at Mach number 0.95,the canopies exhibit ex-tremely severe oscillation when the diameter ratios are 0 and 1.In contrast,in the atmospheric environment of the Ju-piter,when the freestream Mach number is transonic,the change in the projected area of the conical ribbon canopy becomes smaller over time.The drag coefficient and its fluctuation will monotonically increase with the increase of the Mach number,and the lateral force coefficient and its fluctuation reach their maximum at Mach number 1.5.Finally,a comparison is made between the stable descent process of parachutes in the atmospheric environments of the Titan,the Venus,and the Jupiter,showing that the conical ribbon canopy in the Jupiter atmospheric environment has the best performance,a larger drag coefficient,and better stability.
deep space explorationtransonic/supersonic parachutesaerodynamic characteristicsfluid-structure interaction mechanismaerodynamic decelerating technology
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NSTL
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