细长翼偏航/滚转两自由度机翼摇滚的实验研究

Wing rock for a slender wing is studied extensively in unsteady aerodynamics due to its fascination in phenomenon and the engineering background for aircraft flying at high angles of attack. The wing rock motion is primarily a type of coupling oscillatory motion in roll and yaw, along with translational oscillation in side direction and descent. Recent years, the study for wing rock starts to focus on multi-freedom degree motion with the maturity of a single-freedom -degree study. However, because of a limitation of experimental mechanism, the studies for the coupling wing rock with two-freedom-degree in roll and yaw are limited, and the coupling motion patterns and flow mechanism have not been revealed yet. The present proposal aims to study the coupling wing rock in roll and yaw for a slender wing using novel simulated mechanisms with two-freedom-degree. In order to avoid the interference of flow measurements to free motions, such as pressure tubes, the experiments are intended to be carried out by two steps. Firstly, the coupling motion patterns will be obtained using a free-to-roll rig, and then the typical motion patterns are selceted to be replicated using a forced-to-roll rig driven by a servomoter. During the prescribed motion, the surface pressures and spatial flow fields will be measured using pressure scanners and Particle Image Velocimetry (PIV). The investigation will reveal the motion patterns and flow mechanisms dominating the coupling wing-rock motion of a slender wing,thus contributing to unsteady aerodynamics and the development of pratical control techniques of wing rock.

细长三角翼的机翼摇滚问题因其现象上的奇特性及在航空方面的工程背景，一直以来是非定常空气动力学领域的研究热点。机翼摇滚本质上是一种绕偏航和滚转转轴的两自由度耦合振荡运动，同时伴随着质心的侧向平移振荡和下沉。近年来随着单自由度机翼摇滚研究的逐渐完善，研究重点已开始转向多自由度机翼摇滚研究。但由于实验机构的限制，对于偏航滚转两自由度机翼摇滚的实验研究才刚刚起步。本申请拟采用新式的偏航滚转两自由度实验模拟机构，详细研究细长翼偏航滚转两自由度机翼摇滚问题。在测量方法上，为避免流场测量对模型自由运动的干扰，采用两步实验法，首先通过两自由度自由运动机构得到耦合运动形态；再通过强迫运动机构复现该运动历程，并在强迫运动平台上进行测压和PIV流场测量。本项目将揭示细长翼偏航/滚转两自由度机翼摇滚的耦合运动形态和耦合流动机理，在丰富非定常流体力学的研究内容以及发展更为实用的机翼摇滚控制技术方面具有重要科学意义。

绕细长三角翼的旋涡流动和相应的机翼摇滚问题因其现象上的奇特性及在航空方面的工程背景，一直以来是非定常空气动力学领域的研究热点。作为研究细长翼机翼摇滚的基础，首先对模型静态条件下的时均流场和非定常脉动流场开展了相应研究，揭示了前缘涡对的时均非对称性和各种非定常模态。按计划该项目研究了细长三角翼单自由度情况下机翼摇滚的运动学及相应的流场特性，分析了流动和刚体运动的耦合机理。研究了细长翼偏航滚转两自由度情况下机翼摇滚的运动学及流场特性，揭示耦合运动的运动形态和流场特性以及偏航转轴位置对摇滚运动的影响规律。研究过程中，发现了作为模型支撑的机身对三角翼的摇滚特性和流场特性也有较大影响，因而开展了三角翼和翼身组合体机翼摇滚特性的对比研究。该项目也对单独细长体机身上分离涡的非定常开展了初步研究，发现了有趣的流动现象，同时也为进一步的研究提供了思路。本项目揭示了细长翼定常和非定常流动特性以及机翼摇滚的运动与流动特性，在丰富非定常流体力学的研究内容以及发展更为实用的机翼摇滚控制技术方面具有重要科学意义。