具有横向运动能力的圆形伞的设计

Flat circular parachute with lateral mobility

降落伞作为重要的减速工具,通常具备垂直减速能力,若其具备一定的稳定可控横向运动能力,将大大扩展降落伞的应用范围。伞衣上非对称开缝、开孔是实现平飞简单有效的方法。该文基于平面圆形伞设计了具有非对称孔、缝结构的伞型,并通过数值模拟方法计算对比流场结构、阻力系数和横向力系数等结果,验证其是否具备横向运动能力。通过计算可知,距伞底对应圆心角30°处环缝减速效果最佳。在此基础上,将伞的环缝长度缩短一半,并逐步加入径向孔,实现非对称开缝、开孔。在所有计算模型中,U形伞缝的设计会使降落伞的减速性能、横向运动性能有较大提升,同时伞随着迎角变化稳定性最佳。

Parachutes provide rapid vertical deceleration, but are more useful if they also provide stable, controllable lateral movement. A simple, effective method for lateral motion is to cut asymmetrical slits or holes in the canopy. This study simulated flat circular parachute designs with asymmetric holes and slits. The flow fields and the drag and lateral force coefficients of several designs were compared to determine how effectively these parachutes provide lateral motion. The parachute with a 30° annular slit starting from the bottom of the canopy provides the best drag. Further design variations shortened the length of the annular seam and gradually added radial holes. In all the designs, the U-shaped slit greatly improves both the drag and the lateral motion of the parachute and gives the best stability with changes in the angle of attack.