Shock tunnel testing of a Mach 6 hypersonic waverider

A waverider is a lifting body configuration whose upper surface is parallel to the free stream, and the lower surface aerodynamically so designed, that the resulting shock at the design Mach number, is always attached with the leading edge of the vehicle. This prevents spillage from high pressure (lower) surface to the low pressure (upper) surface.In the present study a conical waverider has been designed, fabricated and tested at Mach 6 in the IISc hypersonic shock tunnel HST2. The measurements show that the waverider has a lift to drag ratio of 4.28 at the designed Mach number. Exhaustive FEM and CFD studies are also carried out to complement the force measurements in the tunnel.

飞行高度及设计长度对锥形流乘波体优化的影响 Altitude and Design Length Effects of Optimized Waverider Derived from Cone Flow

高超声速条件下,乘波体布局具有高升阻比特性,本文应用单纯形加速法,以最大升阻比为目标,开展了锥形流乘波体布局优化设计研究.特别是,研究了在高层大气飞行时雷诺数效应与气动特性的关系,从乘波体飞行高度与设计长度两方面探讨雷诺数对乘波体优化的影响,结果表明：给定设计马赫数和圆锥角情况下,对于最大升阻比优化乘波体,其雷诺数越小,摩擦阻力越大,而升阻比越低.

Waverider configurations derived from general conical flowfields

A method based on the computational fluid dynamics (CFD) is presented for a flexible waverider's design. The generating bodies of this method could be any cones. In addition, either the leading edge or the profile of the scramjet's inlet is used as the waverider's definition curve, parameterized by the quadric function, the sigmoid function or the B-spline function. Furthermore, several numerical examples are carried out to validate the method and the relevant codes. The CFD results of the configurations show that all the designs are successful. Moreover, primary suggestions are proposed for practical design by comparing the geometrical and aerodynamic performances of the cone-derived waveriders at Mach 6.

Integration property of a wedge-elliptic cone waverider with scramjet engine

The hypersonic waverider forebody is designed in this paper. For the present waverider, the undersurface is carved out as a stream surface of a hypersonic inviscid flow field around wedge-elliptic cone, and the upper surface is assumed to be a freestream surface. A finite-volume code is used to generate the three-dimensional flow field. The leading edge is determined by satisfying the condition that the lip is situated at the intersection line of shocks.

Aerodynamic characteristics research on wide-speed range waverider configuration

Waverider generated from a given flow field has a high lift-to-drag ratio because of attached bow shock on leading edge. However, leading edge blunt and off-design condition can make bow shock off leading edge and have unfavorable influence on aerodynamic characteristics. So these two problems have always been concerned as important engineering science issues by aeronautical engineering scientists. In this paper, through respectively using low speed and high speed waverider design principles, a wide-speed rang vehicle is designed, which can level takeoff and accelerate to hypersonic speed for cruise. In addition, sharp leading edge is blunted to alleviated aeroheating. Theoretical study and wind tunnel test show that this vehicle has good aerodynamic performance in wide-speed range of subsonic, transonic, supersonic and hypersonic speeds.

Force measurements on hypersonic waveriders in the IISc hypersonic shock tunnel HST2

The drag and lift coefficients for a viscous optimized Mach 6 conical waverider has been measured using an accelerometer force balance system in the IISc hypersonic shock tunnel. A rubber bush placed in between the waverider model and the steel sting ensures unrestrained motion to the model during shock tunnel testing (500 mu s). Two accelerometers mounted on the model are used to measure the model accelerations in the axial and normal directions. The measured value of lift to drag ratio at zero angle of incidence for the IISc conical waverider with viscous optimized leading edge is 2.149, which compares well with the value reported in the open literature (Anderson et al 1991) for similar class of waveriders designed for a flight Mach number of 6. The details of the experimental study along with illustrative numerical results are discussed in this paper.

乘波构形和乘波飞行器研究综述

乘波构形的特点是高升阻比，下表面上的流动是均匀的，因此是推进系统/机身一体化设计的理想候选构形．乘波飞行器是源于乘波构形的高超音速飞行器，利用了乘波构形的高升阻比，并可为吸气发动机提供已知的均匀流场．本文比较全面地总结了乘波构形的生成方法和乘波飞行器的设计方法，介绍了乘波构形的优化方法及影响因素，给出了优化的乘波构形，并介绍了乘波飞行器的研究进展，提出了今后的研究重点．

轴对称近似等熵压缩流场的乘波前体优化设计

以升阻比为优化目标，在来流马赫数Ma＝2～4及飞行高度H＝20km～24km条件下，进行了轴对称近似等熵压缩流场的乘波前体优化设计，通过CFD验证M_∞＝4优化乘波体的气动特性，并研究了Ma＝3优化乘波前体在非设计条件下的气动特性。结果表明：近似等熵压缩下表面的乘波前体在设计条件下具有良好的气流压缩效果，可满足机体／发动机一体化设计的需要；乘波前体升阻比在1.5～1.9之间，纵向压心位置靠后；非设计条件下，压缩波不聚焦，小于设计马赫数升阻比时降低，大于设计马赫数时升阻比略大。

高升阻比乘波构型优化设计

在M∞=6，30km高空条件下，以升阻比为目标函数，进行了锥形流乘波体的黏性优化设计，讨论了影响乘波体升阻比的因素，并对优化结果进行了数值验证．结果表明：对于升阻比最大的黏性优化乘波体，存在最优圆锥角使得源自该基本流场的乘波体升阻比最大；摩阻和波阻处于同一量级；体积率、细长比和展长比都随着基本流场圆锥角的增大而增大．

锥形流乘波体优化设计研究

随着马赫数的升高,波阻和摩阻增加,形成升阻比“屏障”,而乘波构型飞行器是克服这一屏障的有效途径.本文在Ma∞=4.0～20.0、高度H=24.0～52.0 km、圆锥角Ac=5°～10°的条件下,以升阻比为目标函数,进行了乘波体的优化设计,讨论了对乘波体优化外形的影响因素,并给出全马赫数范围的优化乘波体外形及其气动力结果.

The Effect of Conical Flowfields on the Performance of Waveriders at Mach 6

The performance of 23 kinds of waveriders, derived from different conical flowfields, is analyzed by the numerical computation under the conditions of fight speed of Mach 6, attack angle of 0° and flight altitude of 30 km. These results indicate that the performance is influenced by the shapes and the width to height ratios (W/H ) of generating cones. The geometrical parameter and the lift coefficient are proportional to W/H, while the drag coefficient and the lift to drag ratio (L/D ) have extreme values. Considering the base drag and the computation errors, the waverider with the highest L/D is cut from the elliptical cone’s flowfield (W/H = 1.5―1.618), and the configuration with the lowest drag can also be obtained at W/H = 1:1.5. Accordingly, good suggestions are proposed for practical design based on these computational results.

飞行高度及设计长度对锥形流乘波体优化的影响

高超声速条件下,乘波体布局具有高升阻比特性,本文应用单纯形加速法,以最大升阻比为目标,开展了锥形流乘波体布局优化设计研究.特别是,研究了在高层大气飞行时雷诺数效应与气动特性的关系,从乘波体飞行高度与设计长度两方面探讨雷诺数对乘波体优化的影响,结果表明:给定设计马赫数和圆锥角情况下,对于最大升阻比优化乘波体,其雷诺数越小,摩擦阻力越大,而升阻比越低.

滚转运动对乘波飞行器气动特性的影响

乘波飞行器运动过程中的非定常气动特性是高超声速飞行中的重要物理问题之一。采用数值模拟方法模拟了乘波飞行器在固定迎角下绕其对称轴强迫滚转运动这一过程。比较了在不同频率和滚转角下乘波飞行器的气动特性。计算格式采用AUSM类格式中最新的AUSM~+-up格式。计算结果表明:AUSM~+-up能很好地模拟飞行器滚转运动这一非定常过程;滚转运动时,所设计的乘波飞行器能使高压气体很好地附着在乘波飞行器下表面从而使其具有较好的气动特性;当频率较大时,乘波飞行器由于角速度的诱导作用会导致升力出现迟滞现象;做滚转运动时,滚转力矩小于零,产生正阻尼,乘波飞行器不会产生"摇滚"运动.