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Aerodynamic control of slender bodies from low to high angles of attack through flow manipulation.

机译:通过流动操纵,从低到高攻角对细长体进行气动控制。

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This dissertation presents experimental investigations of several novel active flow control methodologies that have been implemented for aerodynamic control and maneuvering of slender bodies at low and high angles of attack through flow manipulation. For low angles of attack, a U.S. Army Smart Cargo projectile was examined. For high angles of attack a U.S. Air Force countermeasure concept projectile termed DEX (Destructive Expendable) was examined.; Low angle of attack control was attempted using two novel separation control techniques: reconfigurable porosity and miniature deployable spoilers. Results show that significant aerodynamic forces are generated by implementing reconfigurable porosity and can be effectively used to steer and maneuver air vehicles. Porous patterns with a "saw-tooth" configuration seem to be the most effective in generating consistent control forces over a wide range of angles of attack. Miniature deployable spoilers successfully demonstrated their ability in producing both positive and negative pitch and yaw controls by modulating the spoiler height and length when used on the boattail and Aero Control Fins (ACFs) of a projectile.; The effect of aftbody strake parameters such as shape, locations (axial and azimuthal), deployment height, and number of strakes implemented was examined on a short blunt-nose projectile. Large yaw control authority was attained for alpha > 40 deg. The largest yaw control authority was produced by a rectangular-shaped strake.; A robust closed-loop feedback controller was successfully tested using dynamic wind tunnel experiments to control the coning motion of a projectile. The controller showed good control authority and was capable of attaining and maintaining the commanded roll angle with a tolerance of +/-10 deg.; A study was conducted to gain some insights into the fluid mechanics of short blunt-nose bodies of revolution at high angles of attack. Off- and on-surface flow visualization records are collected to study the effects of two blunt noses: a hemispherical nose and an elliptical nose with 33% ellipticity. It was found that the elliptical-nose results in flow behaviors typical of a blunt-nose, while the hemispheric-nose results in behaviors that are akin to a pointed-nose. An explanation for the contrasting behaviors is provided.
机译:本文提出了几种新颖的主动流动控制方法的实验研究,这些方法已通过气流操纵实现了在低攻角和高攻角下的细长体的气动控制和操纵。对于低攻角,检查了美国陆军的智能货运子弹。对于高攻角,研究了一种称为DEX(破坏性消耗品)的美国空军对策概念射弹。使用两种新颖的分离控制技术尝试了低攻角控制:可重新配置的孔隙率和微型可展开扰流板。结果表明,通过实现可重构的孔隙率会产生很大的空气动力,并且可以有效地用于操纵和操纵飞机。具有“锯齿”形状的多孔图案似乎在最宽的攻角范围内产生一致的控制力方面最为有效。微型可展开扰流板通过调节在弹丸的船尾和航空控制鳍片(ACF)上使用时扰流板的高度和长度,成功展示了产生正,负俯仰和偏航控制的能力。在一个短钝头的弹丸上检查了后方机体参数的影响,例如形状,位置(轴向和方位角),展开高度和所执行的机体数量。当alpha> 40度时,可获得较大的偏航控制权。最大的偏航控制权是由矩形的板条产生的。鲁棒的闭环反馈控制器已通过动态风洞实验成功地进行了测试,以控制弹丸的​​圆锥运动。控制器显示出良好的控制权限,并且能够以+/- 10度的公差获得和维持命令的侧倾角;进行了一项研究,以期获得一些短的钝角旋转体在高攻角下的流体力学的见解。收集了表面和表面上的流动可视化记录,以研究两个钝鼻子的影响:半球形鼻子和椭圆率为33%的椭圆鼻子。已经发现,椭圆形鼻孔导致了典型的钝鼻流动行为,而半球形鼻孔导致了类似于尖鼻的流动行为。提供了对比行为的说明。

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