999 resultados para Supersonic flow
Resumo:
通过求解三维可压缩N-S方程组，对尖锥／圆柱组合体模型在超音速绕流中的侧向喷流干扰流场进行了模拟，数值方法采用有限体积法，差分格式采用NND格式。分析了干扰流场的结构，研究了干扰效应对气动性能的影响，得到来流Ma。。=3．3和4．5时力放大因子和干扰力矩系数随攻角变化的规律，计算结果与实验一致。
Resumo:
The two-dimensional accelerating theory about solar wind is applied to the study of theaccelerating process of jet beam in the radio galaxy. The flowing features are given with theanalytic method, and the basic flow is along the direction of the jet beam. The mechanism ofacceleration from subsonic to supersonic flow is discussed. At the same time, some fine struc-tures about the double sources in the radio galaxy are explained.
Resumo:
本文集共收录了作者24篇期刊论文和研究报告。其中，1943～1955年期间发表的14篇论文内容涉及直管中的可压缩流动、有限振幅柱面和球面波的传播、可压缩流体二维无旋亚声速、超声速混合型流动和上临界马赫数、光滑跨声速绕流及其稳定性、斜激波从平板边界层的反射、中等雷诺数下绕平板的流动等。1956～1957年期间发表的5篇论文：绕平板和楔的高超声速流动、普朗特数和解离对高超声速流动的影响以及增补的5篇文章是作者在高超声速流动领域的研究成果以及他在回国后的学术报告和发表的文章，涉及现代空气动力学的发展方向、发射卫星和返地回收的科学和技术问题，体现了他在参与“两弹一星”技术领导工作中的学术思想。2 The flow of a compressible viscous fluid through a straight pipe.（可压缩黏性流体在直管中的流动1943年）
3 Two dimensional irrotational mixed subsonic and supersonic flow of a compressible fluid and the upper critical Mach number（可压缩流体二维无旋亚声速和超声速混合型流动及上临界马赫数1946年）
4 On the stability of transonic flows（论跨声速流的稳定性1947年）
5 The propagation of a spherical or a cylindrical wave of finite amplitude and the production of shock waves（有限振幅球面波或柱面波的传播及激波的产生1947年）
6 Two-dimensional irrotational transonic flows of a compressible fluid（可压缩流体二维无旋跨声速流动1948年）
7 On the hodograph method（关于速度图方法1949年）
8 Two-dimensional transonic flow past airfoils（绕翼型的二维跨声速流1951年）
9 On the stability of two-dimensional smooth transonic flows（论二元光滑跨声速流的稳定性1951年）
10 On the flow of an incompressible viscous fluid past a flat plate at moderate Reynolds numbers（中等雷诺数下不可压缩黏性流体绕平板的流动1953年）
11 Reflection of a weak shock wave from a boundary layer along a flat plate.I：Interaction of weak shock waves with laminar and turbulent boundary lavers analyzed by momentum-integral method（弱激波从沿平板的边界层的反射Ⅰ：用动量积分方法分析弱激波与层流和湍流边界层的相互作用1953年）
12 Reflection of weak shock wave from a boundary layer along a flat plate.Ⅱ：Interaction of oblique shock wave with a laminar boundary layer analyzed by differential-equation method（弱激波从沿平板的边界层的反射Ⅱ：用微分方程方法分析斜激波与层流边界层的相互作用1953年）
13 Plane subsonic and transonic potential flows（平面亚、跨音速势流1954年）
14 A similarity rule for the interaction between a conical field and a plane shock（锥型流和激波相互作用的相似律1955年）
15 Viscous flow along a flat plate moving at high supersonic speeds（沿高超声速运动平板的黏性流动【Ⅰ】1956年）
16 Viscous flow along a flat plate moving at high supersonic speeds（沿高超声速运动平板的黏性流动【Ⅱ】1956年）
17 The effects of Prandtl number on high-speed viscous flows over a flat plate（Prandtl数对绕平板高速黏性流的影响1956年）
18 Compressible viscous flow past a wedge moving at hypersonic speeds（楔的高超声速可压缩黏性绕流1956年）
19 Dissociation effects in hypersonic viscous flows（高超声速黏性流动中的离解效应1957年）
20 现代空气动力学的问题（1957年）
2l 在关于苏联发射成功第一颗人造卫星座谈会上的发言记录（1957年）
22 高超速钝体湍流传热问题（1963年）
23 宇宙飞船的回地问题（1965年）
24 激波的介绍
郭永怀生平
郭永怀传
Resumo:
在高超声速飞行条件下，流入冲压发动机燃烧室并降至低速的空气的温度随飞行马赫数增加而愈来愈高。燃料与高温空气混合燃烧释放的化学能中的一部分将转化为解离能。这些解离能在长度受限的尾喷管中难以充分复合形成推力，使冲压发动机推力在高超声速范围内随飞行马赫数增大而下降，难以满足高超声速飞行器的推进要求。 与亚燃冲压发动机相比，流入超燃冲压发动机燃烧室的空气的温度在同样飞行马赫数条件下将明显降低，上述困难可大大缓解。然而目前超燃冲压发动机还存在关键性难点有待克服。若保持现有亚燃冲压发动机的吸气与燃烧方式，通过催化促进燃气解离组分在尾喷管膨胀过程中复合，可以增大冲压发动机的推力，满足高超声速飞行器的推进要求，为高超声速飞行器推进提供新的选择。 本论文主要研究内容如下： （1） 研究了亚燃冲压发动机燃烧室内燃气解离能与飞行马赫数的关系。通过对冻结流、平衡流和有限化学反应速率的流动的数值计算，确定了回收解离能增大推力的潜力。 （2） 以双爆轰技术为基础，建立起一套地面燃气产生装置。所产生的燃气的组分、温度和压力均与冲压发动机在高空飞行时燃气完全相同。调试出总温3200K、总压20Bar（对应来流马赫数6）和试验时间17.5ms以及总温4000K、总压5Bar（对应来流马赫数8）和试验时间12.5ms两种状态参数的试验用燃气。 （3） 建立了基于动量守恒原理的通过皮托管测压力换算推力的测量方法。对催化复合增大推力的实验而言，一般要进行特定流动条件下喷水与未喷水两种情况下推力大小的比较，其精度可以达到2%甚至更高。 （4） 完成了尾喷管喉道下游管壁喷水试验，成功释放出高温燃气中的解离能，有效增大了推力，证实了催化增推的想法是可行的。在来流马赫数6的条件下获得了11.0%的推力增量；在来流马赫数8.0的条件下也获得了11.7%的推力增加。
Resumo:
An experimental investigation into the response of transonic SBLIs to periodic down-stream pressure perturbations in a parallel walled duct has been conducted. Tests have been carried out with a shock strength of M ∞ = 1.5 for pressure perturbation frequencies in the range 16-90 Hz. Analysis of the steady interaction at M∞ = 1.5 has also been made. The principle measurement techniques were high speed schlieren photography and laser Doppler anemometry. The structure of the steady SBLI was found to be highly three-dimensional, with large corner flows and sidewall SBLIs. These aspects are thought to influence the upstream transmission of pressure information through the interaction by affecting the post-shock flow field, including the extent of regions of secondary supersonic flow. At low frequency, the dynamics of shock motion can be predicted using an inviscid analytical model. At increased frequencies, viscous effects become significant and the shock exhibits unexpected dynamic behaviour, due to a phase lag between the upstream transmission of pressure information in the core flow and in the viscous boundary layers. Flow control in the form of micro-vane vortex generators was found to have a small impact on shock dynamics, due to the effect it had on the post-shock flow field outside the viscous boundary layer region. The relationship between inviscid and viscous effects is developed and potential destabilising mechanisms for SBLIs in practical applications are suggested. Copyright © 2009 by Paul Bruce and Holger Babinsky.
Resumo:
Inflatable aerodynamic decelerators present potential advantages for planetary entry in missions of robotic and human exploration. The design of these structures face many engineering challenges, including complex deformable geometries, anisotropic material response, and coupled shockturbulence interactions. In this paper, we describe a comprehensive computational fluid-structure interaction study of an inflation cycle of a tension cone decelerator in supersonic flow and compare the simulations with earlier published experimental results. The aeroshell design and flow conditions closely match recent experiments conducted at Mach 2.5. The structural model is a 16-sided polygonal tension cone with seams between each segment. The computational model utilizes adaptive mesh refinement, large-eddy simulation, and shell mechanics with self-contact modeling to represent the flow and structure interaction. This study focuses on the dynamics of the structure as the inflation pressure varies gradually, and the behavior of forces experienced by the flexible and rigid (the payload capsule) structures. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
