共查询到19条相似文献,搜索用时 140 毫秒
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真实火箭射流冲击流场中激波结构的实验研究 总被引:3,自引:0,他引:3
本文采用一种有效的激光-莫瑞光栅干涉系统首次拍摄到真实火箭燃气射流冲击流场的激波结构.解决了长期以来无法拍摄到高温、高速、强火焰光的火箭射流流场图像的问题。利用这一系统,研究了射流冲击流场中激波结构的一些变化规律,发现了一些新的激波结构。较系统地研究了欠膨胀射流冲击各种锥体的激波形态。 相似文献
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基于Navier-Stokes方程组,采用可压缩多介质黏性流动和湍流大涡模拟程序MVFT (multi-viscousflow and turbulence),模拟了均匀流场与初始密度呈现高斯函数分布的非均匀流场中马赫数为1.25的非平面激波加载初始扰动air/SF6界面的Richtmyer-Meshkov (RM)不稳定性现象。数值模拟结果表明,初始流场非均匀性将会影响非平面激波诱导的RM不稳定性演化过程。反射激波加载前,非平面激波导致的界面扰动振幅随着流场非均匀性增强而增大;反射激波加载后,非均匀流场与均匀流场条件下的界面扰动振幅差异有所减小。进一步,定量分析流场中环量分布及脉动速度统计量揭示了前述规律的原因。此外,还与平面激波诱导的RM不稳定性进行了简单对比,发现由于非平面激波波阵面区域的涡量与激波冲击界面时产生的涡量的共同作用,使得非平面激波与平面激波诱导的界面失稳过程存在差异。 相似文献
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运动物体与运动激波干扰流场特性数值研究 总被引:1,自引:0,他引:1
用数值方法求解非定常可压缩Navier—Stokes方程,模拟了运动物体分别以超声速和亚声速穿越激波的全过程。在这两种情况下,激波都是从高压区运动到低压区,阻力急剧地减小,但在亚声速情况下,会在物体上产生不对称力和力矩,导致运动物体的不稳定。 相似文献
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界面不稳定性, 特别是Richtmyer–Meshkov (RM) 不稳定性, 是流体力学中一项重要的研究内容, 无论在学术研究领域还是工程应用领域都有着重要的研究价值和应用背景. RM 不稳定性问题自提出以来, 得到了学术界广泛的关注, 其研究无论是在实验方法、数值模拟还是在理论分析方面都取得了很大的进展. 在激波管中开展激波与界面相互作用的实验研究, 即研究界面初始扰动在激波诱导下的演化规律, 是目前研究RM 不稳定性的重要手段. RM 不稳定性实验研究包括3 个部分, 分别是激波的产生、界面的形成以及流场的观测. 综述了RM 不稳定性的实验研究进展, 并针对目前研究的局限性提出了RM 不稳定性今后实验研究的重点和方向: 汇聚激波作用下界面不稳定性的发展规律; 激波冲击下多种形状及大振幅界面的演化机理; 三维界面的RM 不稳定性发展规律; 可压缩湍流的形成与混合机理. 相似文献
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本文提出了轴向流固定反应器的流动模型和基本方程。运用有限差会计了这种反应器内部的流场。 相似文献
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本文提出了轴向流固定床反应器的流动模型和基本方程。运用有限差分法计算了这种反应器内部的流场。 相似文献
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Tang Guiming 《Acta Mechanica Sinica》1998,14(2):139-146
An experimental study was conducted on shock wave turbulent boundary layer interactions caused by a blunt swept fin-plate
configuration at Mach numbers of 5.0, 7.8, 9.9 for a Reynolds number range of (1.0∼4.7)×107/m. Detailed heat transfer and pressure distributions were measured at fin deflection angles of up to 30° for a sweepback
angle of 67.6°. Surface oil flow patterns and liquid crystal thermograms as well as schlieren pictures of fin shock shape
were taken. The study shows that the flow was separated at deflection of 10° and secondary separation were detected at deflection
of ϑ≥20°. The heat transfer and pressure distributions on flat plate showed an extensive plateau region followed by a distinct
dip and local peak close to the fin foot. Measurements of the plateau pressure and heat transfer were in good agreement with
existing prediction methods, but pressure and heating peak measurements atM≥6 were significantly lower than predicted by the simple prediction techniques at lower Mach numbers.
The project supported by China Academy of Launch Vehicle Technology 相似文献
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爆炸去磁脉冲功率发生器的实验和理论计算 总被引:2,自引:0,他引:2
设计了两种结构的爆炸去磁脉冲功率发生器:炸药透镜平面波冲击加载圆柱形磁体和中心装药冲击加载圆环形磁体,磁体材料都采用Nd2Fe14B永磁体。进行了爆炸冲击加载实验,测量了爆炸去磁脉冲发生器的输出电流、电压以及Nd2Fe14B永磁体中的冲击波速度。通过对爆炸去磁脉冲功率发生器基本原理的分析,建立了感生电动势的理论计算方法。用Maxwell 3D电磁场分析软件,对Nd2Fe14B永磁体进行了静磁场分析,给出了Nd2Fe14B永磁体的磁场强度分布规律。实验结果表明:爆炸去磁脉冲功率发生器每匝线圈能够产生约67 V的感生电动势,对于0.56 H的电感负载能够输出脉宽78.3 s、峰值1 212 A的脉冲电流。 相似文献
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One of the more severe fluctuating pressure environments encountered in supersonic orhypersonic flows is the shock wave oscillation driven by interaction of a shock wave withboundary layer.The high intensity oscillating shock wave may induce structure resonanceof a high speed vehicle.The research for the shock oscillation used to adopt empirical orsemiempirical methods because the phenomenon is very complex.In this paper atheoretical solution on shock oscillating frequency due to turbulent shear layer fluctuationshas been obtained from basic conservation equations.Moreover,we have attained theregularity of the frequency of oscillating shock varying with incoming flow Mach numbersM_∞and turning angleθ.The calculating results indicate excellent agreement withmeasurements.This paper has supplied a valuable analytical method to study aeroelasticproblems produced by shock wave oscillation. 相似文献
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A combined theoretical and experimental study is presented for the interaction between crossing shock waves generated by (10°, 10°) sharp fins and a flat plate turbulent boundary layer at Mach 8.3. The theoretical model is the full 3-D mean compressible Reynolds-averaged Navier-Stokes RANS) equations incorporating the algebraic turbulent eddy viscosity model of Baldwin and Lomax. A grid refinement study indicated that adequate resolution of the flowfield has been achieved. Computed results agree well with experiment for surface pressure and surface flow patterns and for pitot pressure and yaw angle profiles in the flowfield. The computations, however, significantly overpredict surface heat transfer. Analysis of the computed flowfield results indicates the formation of complex streamline and wave structures within the interaction region.This article was processed using Springer-Verlag TEX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society. 相似文献
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Aerodynamic heating in the region of shock and turbulent boundary layer interaction induced by a cylinder 总被引:1,自引:0,他引:1
Detailed distributions of heat flux in the region of shock wave and turbulent boundary layer interaction induced by a cylinder
were measured in the shock tunnel. Oil flow patterns and Schlieren photographs were taken. Empirical relations were given
for determining separation shock angle, peaks of heat flux and their locations on both cylinder leading edge and flat plate
surface, and other characteristic parameters of the interaction region. 相似文献
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Hypersonic perfect gas flow past the weakly curved end face of a circular cylinder is considered in the thin shock layer approximation. Regimes in which the shape of the end face is not a monotonic function of the radius but contains, for example, a central body of variable height are studied. It is found that, as the central body is extended, a break is formed in the slope of the shock. Smoothing takes place in a short zone of interaction between the main part of the thin shock layer, the shock, and the small near-wall potential jet. The solution, which depends continuously on a parameter, exists over a limited height range and bifurcates when a critical value is exceeded. 相似文献
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Comparison of kinetic and continuum approaches for simulation of shock wave/boundary layer interaction 总被引:1,自引:0,他引:1
I.A. Graur M.S. Ivanov G.N. Markelov Y. Burtschell E. Valerio D. Zeitoun 《Shock Waves》2003,12(4):343-350
The present paper, which is a collaboration between three different research groups, analyzes the efficiency of various numerical
approaches to describe the complex problem of shock wave/boundary layer interaction. Computations were carried out based on
a kinetic approach (Direct Simulation Monte Carlo method) and on two continuum approaches (Navier-Stokes equations and quasigasdynamic
equations), which are validated by comparison with experimental results obtained in the R5Ch blowdown Hypersonic Wind Tunnel
in ONERA. The influence of the slip boundary conditions for two continuum approaches are also studied. The results obtained
by all models display the good prediction of the main structure of the flow and the levels of the flux coefficients are very
close to those measured. The implementation of the slip boundary condition for the continuum approaches improves the agreement
with the experimental data.
Received 12 July 2001 / Accepted 24 May 2002 /Published online 4 December 2002
Correspondence to: D. Zeitoun (e-mail: David.Zeitoun@polytech.univ-mrs.fr)
An abridged version of this paper was presented at the 23rd Int. Symposium on Shock Waves at Fort Worth, Texas, from July
22 to 27, 2001 相似文献
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In this paper computational results for two different types of shock wave / turbulent boundary layer interaction flows are presented. It is shown that upstream effects of the shock induced separation cannot be reproduced by Wilcox's (1991) k--model, whereas downstream of the interaction, predictions of pressure distribution and skin friction are acceptable. The inclusion of the compressible part of the dissipation rate and the pressure dilatation in the model has noticeable, but not dramatic effects on wall pressure and skin friction in the selected flow cases. 相似文献