RESEARCH ON DELTA WING UNSTEADY HIGH ANGLE OF ATTACK AERODYNAMICS

本研究旨在研究三角翼大迎角下与翼岩相关的流体力学现象的基本物理细节。介绍了一种特殊设计的双分量平衡强制滚转振荡方法，用于测量气动力和力矩；不采用常规的自由旋转方法。该方法的成功取决于从测量中准确分离惯性力和气动力。使用重量轻的模型，低振荡率和平衡的精心校准使数据达到0.1的无因次滚动率成为可能。对两种半顶点角分别为14度和7度的三角翼模型进行了试验，结果表明，较小顶点角的三角翼模型表现出非常复杂的气动特性。通过对比平衡输出和流动显示图像，可以清楚地看到这些变化的原因与旋涡破裂和旋涡分裂有关。

This research is to study the basic physical details of the fluid dynamic phenomena associated with the wing rock observed at hjgh angles of attack on delta wings. A specially designed forced roll oscillation method with a two-components balance was introduced to take the aerodynamic force and moment ; not adopting the conventional free rotation methods. The success of the method depends on the accurate separation of the inertial and aerodynamic forces from the measurement. Use of light weight models, low rate of oscillation and elaborate calibration of balances made it possible to get data up to the non-dimensional roll rate of 0.1.Two delta wing models of 14 and 7 degree semi-apex angle, respectively, are put to the tests and the model with a smaller apex angle shows very complicated aerodynamics. The reason of these changes are mode clear in relation to the vortex breakdown and vortex splitting by comparing the blance outputs with the flow visualization pictures.