| Ram-air parafoil has high lift-drag ratio,remarkable turning performance,and flare maneuver performance.It is widely used in civil,military,aerospace and other fields.Currently,the research of parafoil mostly relies on airdrop tests,which is costly and limited in obtaining information.Wind field changes random and their impacts on system are difficult to measure.Therefore,based on ALE fluid-structure interaction method,this thesis studies the motion and trajectory characteristics of a parafoil system during its descending progress under different wind conditions.Firstly,a projectile-parachute system’ geometry and its folded grid model was established.The effects of different wind speeds,wind directions,and initial trajectory angles on the motion characteristics of this parachute projectile system are analyzed.The variation of the trajectory,velocity,trajectory angle,and swing angle of the system under different conditions are obtained,verifying the applicability and feasibility of the ALE method in the parachute opening process and stable landing process.Secondly,a ram-air parafoil model is established,and six different wind directions along the X/Y/Z axis are utilized.The fluid-structure interaction numerical simulation of the parafoil system opening process and stable landing process with different wind speeds and directions are carried out.The dynamic changes in canopy shape,parafoil span,trajectory,and attitude are obtained.The results show that the impacts of wind field on parafoil is asymmetric.The wind field exerts an additional force on the system along the wind direction,causing the system to move along,and the displacement deviation is positively correlated with the wind speed.The roll angle of the system is greatly affected by the crosswind.Rolling range is positively correlated with the wind speed,parafoil will roll backward after reaching the peak rolling angle.It provides some reference for the parafoil design and trajectory optimization. |
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