Control of Vortex Breakdown-Fin Interaction on a Delta Wing

现代高性能飞机利用旋涡流来增强机动性和操控性。在飞机上不同位置产生的流向涡可以与尾翼和尾翼相互作用，从而导致流致振动。近年来，人们对飞机模型的各种附属物以及飞机的简单三角翼表示进行了大量的涡旋撞击研究。与飞机的几何细节无关，破碎的旋涡与下游附属物的相互作用预计会表现出某些通用特征。本研究的目的是将发生在鳍上的涡击穿的集合平均和瞬时结构与沿鳍的表面压力谱联系起来。高像密度粒子图像测速（PIV）用于确定速度场和涡度分布，从而导致压力谱的物理解释。更多的瞬时速度场和平均速度场的组合，结合涡度波动的均方根表示，为相应的压力谱提供了合理的基础，并在鳍表面的关键位置进行了测量。为了便于激光诊断，将三角翼-鳍系统安装在水道中的倒立位置，使机翼处于负攻角。瞬时速度场和表面压力测量是在从三角翼尾缘到机翼前缘的两个不同距离上获得的。机翼的这种倒置位置可以获得视场上速度的瞬时图像。破碎涡撞击前缘掠过的翅片时，会产生复杂的流动结构，并在翅片表面形成大面积分离区。本文着重建立了破碎涡入射到翅片上的瞬时速度场和涡量场与沿翅片前缘区域引起的表面压力波动之间的关系，以及该流动的主要特征和相关压力波动情况如下

Modern high performance aircraft exploit vortex flows for enhanced maneuverability and control. Streamwise vortices, which are generated at various locations on the aircraft, can interact with fins and tails, and result in flow-induced vibration. In recent years, there have been a number of studies of vortex impingement upon various appendages of models of the aircraft as well as simple delta wing representations of aircraft. The interaction of broken-down vortices with downstream appendages is expected to exhibit certain generic features irrespective of the geometrical details of the aircraft.The objective of this study is to relate the ensemble-averaged and instantaneous structure of vortex breakdown incident upon a fin to spectra of surface pressure along the fin. High-image-density particle image velocimetry (PIV) is used to determine the velocity fields and vorticity distributions, which, in turn, lead to a physical interpretation of the pressure spectra. Various combinations of i … More nstantaneous and averaged velocity fields, in conjunction with root-mean-square representations of vorticity fluctuations, provide a rational basis for the corresponding pressure spectra, which are measured at crucial locations on the surface of the fin.The delta wing-fin system was mounted in an inverted position in the water channel, such that the wing was at a negative angle of attack, in order to facilitate laser diagnostics. Instantaneous velocity fields and surface pressure measurements were obtained at two different distances from the trailing-edge of the delta wing to the leading-edge of the fin. This inverted position of the wing allowed acquisition of instantaneous images of the velocity over the fields of view.Impingement of a broken-down vortex on a fin having a swept leading-edge generates a complex flow structure associated with a large-scale separation zone extending over the surface of the fin. This paper is focused on establishing a relationship between the instantaneous velocity and vorticity fields of a broken-down vortex incident upon a fin and the surface pressure fluctuations induced along the leading-edge region of a fin. The principal features of this flow and the associated pressure fluctuations are as follows: Less