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1.
In this paper, numerical simulation of three-dimensional supersonic flow in a duct is presented. The flow field in the duct is complex and can find its applications in the inlet of air-breathing engines. A unique streamwise marching Lagrangian method is employed for solving the steady Euler equations. The method was first initiated by Loh and Hui (1990) for 2-D steady supersonic flow computations and then extended to 3-D computation by the present authors Loh and Liou (1992). The new scheme is shown to be capable of accurately resolving complicated shock or contact discontinuities and their interactions. In all the computations, a free stream of Mach numberM=4 is considered.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
2.
Numerical confirmation of the hysteresis phenomenon in the regular to the Mach reflection transition in steady flows 总被引:1,自引:0,他引:1
Numerical calculations based on the Navier-Stokes equations are carried out to investigate the reflection of shock waves over straight reflecting surfaces in steady flows. The results for a flow Mach number of M0=4.96 confirm the recent experimental findings of Chpoun et al. (1995) concerning the transition from regular to Mach reflection. Numerical calculations as well as experimental results show a hysteresis phenomenon during this transition and the regular reflection is found to be stable in the dual-solution domain in which theoretically both regular and Mach reflection wave configurations are possible. 相似文献
3.
In this paper, an unsplit random choice method (RCM) is developed and applied to numerically solve three‐dimensional supersonic steady flow problems. In order to keep the contacts (slip surfaces) crisply resolved, a new Lagrangian formulation is employed. Due to the lack of exact solutions to 3D Riemann problems, approximate Riemann solutions in the weak sense are adopted. The RCM is thus as efficient as the deterministic TVD schemes, and yields almost identical results in the model problems. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
4.
Supersonic flows near flying vehicle elements are calculated in the approximation of the full Navier-Stokes equations for
a viscous compressible heat-conducting gas with different values of free-stream. Mach and Reynolds numbers and angles of attack.
The main laws of the flow near the lifting surface. and in the inlet are obtained.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 2, pp. 98–108, March–April, 2009. 相似文献
5.
This study employs the Space-Time Conservation Element and Solution Element (CE/SE) method to determine the influence of downstream
flow conditions on Mach stem height. The results indicate that the Mach stem height depends on the incident shock wave angle
and the distance between the trailing edge and the symmetry plane. Furthermore, it is shown that the downstream length ratio
and the trailing edge angle do not affect the Mach stem height nor the Mach reflection (MR) configuration, and the Space-Time
Conservation Element and Solution Element method is able to simulate the MR as well as many other numerical schemes.
Communicated by K. Takayama
PACS 47.40.Nm 相似文献
6.
The gap effect is a key factor in the design of the heat sealing in supersonic vehicles subjected to an aerodynamic heat load. Built on S-A turbulence model and Roe discrete format, the aerodynamic environment around a gap on the surface of a supersonic aircraft was simulated by the finite volume method. As the presented results indicate, the gap effect depends not only on the attack angle, but also on the Mach number. 相似文献
7.
Supersonic (M∞ = 2−5) turbulent flows in the vicinity of a two-dimensional backward-facing step with an inclined leeward side are considered
by methods of mathematical modeling. The wave structure of the flow with a varied angle of inclination of the leeward side
of the step and a varied free-stream Mach number is considered.
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Translated From Prikladnaya Mekhanika I Tekhnicheskaya Fizika, Vol. 47, No. 6, pp. 48–58, November–December, 2006. 相似文献
8.
The head-on collision and subsequent reflection of a Regular Reflection (RR) from the end-wall of a shock tube has been investigated both experimentally and numerically for two different incident shock wave Mach numbers and two different reflecting wedge angles. The agreement between the double-exposure holographic interferograms and the numerical simulations which were obtained using a GRP based numerical code, was found to be excellent in the RR region and very good behind the head-on reflected RR. The overall good agreement between the computed and experimental constant-density contours (isopycnics) constitutes a validation of the computational method, including the oblique-wall boundary condition. 相似文献
9.
The behavior of the vorticity vector on a discontinuity surface arising in a supersonic nonuniform combustible gas flow with
the formation of a shock or detonation wave is studied. In the general case, it is a vortex flow with prescribed distributions
of parameters. It is demonstrated that the ratio of the tangential component of vorticity to density remains continuous in
passing through the discontinuity surface, while the quantities proper become discontinuous. Results calculated for flow vorticity
behind a steady-state detonation wave in an axisymmetric supersonic flow of a combustible mixture of gases are presented.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 15–21, November–December, 2007 相似文献
10.
Transformation of energy and composition of gas mixtures in a collision of rarefied supersonic flows
Transformation of energy and composition of gas mixtures in a convergent flow from a strip source on a cylindrical surface
toward the axis is systematically studied with the use of the direct simulation Monte Carlo method. Information on the influence
of gas-flow rarefaction and system geometry on the temperature and concentration of the heavy gas in a dense cloud formed
on the axis is obtained. The use of convergent supersonic flows is demonstrated to offer new possibilities for research in
the field of physical gas dynamics.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 2, pp. 198–204, March–April, 2009 相似文献
11.
One-dimensional analytical theory is developed for supersonic duct flow with variation of cross section, wall friction, heat addition, and relations between the inlet and outlet flow parameters are obtained. By introducing a selfsimilar parameter, effects of heat releasing, wall friction, and change in cross section area on the flow can be normalized and a self-similar solution of the flow equations can be found. Based on the result of self-similar solution, the sufficient and necessary condition for the occurrence of thermal choking is derived. A relation of the maximum heat addition leading to thermal choking of the duct flow is derived as functions of area ratio, wall friction, and mass addition, which is an extension of the classic Rayleigh flow theory, where the effects of wall friction and mass addition are not considered. The present work is expected to provide fundamentals for developing an integral analytical theory for ramjets and scramjets. 相似文献
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14.
Numerical simulations have been performed to investigate the stability of shock wave reflection in supersonic steady flow.
Wall deflection control has been applied just downstream of the reflection point in the regular reflection configuration.
The results provide the magnitude of the disturbance required to cause transition from one configuration to the other throughout
the range of incident shock angle. An argument focusing on the subsonic region generated behind the Mach stem in the Mach
reflection configuration explains the mechanism of the transition. Numerical results show that both regular and Mach reflections
are possible in the dual-solution domain, and also indicate the presence of the hysteresis effect. The transition processes
and the stability of the possible states are shown to be described consistently by an analogy based on the potential energy
of a particle on a surface. The necessity of more sophisticated experimental investigations is emphasized to verify the argument
about the stability of shock reflections and proposed analogy.
Received 17 March 1997 / Accepted 26 February 1998 相似文献
15.
We present a high resolution numerical solution of the Vasilev reflection configuration within the framework of depth averaged
two-dimensional inviscid shallow water flow. The study provides the details of the steady flow field and shock wave pattern
close to the triple point which confirm the four-wave theory. The shape of the reflected shock in the region upstream of the
supercritical patch is also investigated.
相似文献
16.
In a shock tube the pressure distribution was measured on a cone with an angle of attack when a shock wave passed the cone.
The cone has a semi-apex angle of 35°, the angle of attack varied from 0° to 25° and the shock Mach numbers from 1.05 to 3.0.
A series of pressure distributions on the cone circumference are given.
Received 17 November 1997 / Accepted 5 December 1997 相似文献
17.
The unsteady aspects of shock-induced-separation patterns have been investigated inside a Mach 2 planar nozzle. The mean location
of the shock can vary by changing, relatively to the nozzle throat, the height of the second throat which is positioned downstream
of the square test section. This study focuses on the wall pressure fluctuations spectra and the unsteady behaviour of the
shock. Symmetric shock configurations appear both for the largest openings of the second throat, and for the smallest openings.
For an intermediate opening the shock system exhibits asymmetrical configurations. A coating with roughnesses sticked on the
throat part of the nozzle in order to modify the state of the incoming boundary layers (from smooth to rought turbulent statement)
is a driver for the asymmetry. The fluctuating displacements of the shock patterns were analysed by using an ultra fast shadowgraph
visualization technique. A spectral analysis of the unsteady wall pressure measurements has revealed low frequency phenomena
governed by large structure dynamics in the separated flows.
Communicated by K. Takayama
PACS 02.60.Cb; 05.10.Ln; 47.11.+j; 47.15.Cb; 47.40.Nm 相似文献
18.
研究了在无粘完全气体流中的运动激波 ,讨论了激波运动速度D和来流速度U对激波后气流参数的影响 ,包括对激波后的总焓比值和总压比值以及对流转角的影响。计算结果表明它们不同于通常静止激波下所得到的结果。该内容涉及到超音速射流与障碍物或空腔体相互作用时出现的失稳状态下激波的振动和空腔体底部的反常加热问题。 相似文献
19.
The problem of transition of planar shock waves over straight wedges in steady flows from regular to Mach reflection and
back was numerically studied by the DSMC method for solving the Boltzmann equation and finite difference method with FCT algorithm
for solving the Euler equations. It is shown that the transition from regular to Mach reflection takes place in accordance
with detachment criterion while the opposite transition occurs at smaller angles. The hysteresis effect was observed at increasing
and decreasing shock wave angle.
Received September 1, 1995 / Accepted November 20, 1995 相似文献
20.
This paper presents a mathematical model for describing approximately the viscoelastic effects in non-Newtonian steady flows through a porous medium. The rheological behaviour of power law fluids is considered in the Maxwell model of elastic behaviour of the fluids. The equations governing the steady flow through porous media are derived and an analytical solution of these equations in the case of a simple flow system is obtained. The conditions for which the viscoelastic effects may become observable from the pressure distribution measurements are shown and expressed in terms of some dimensionless groups. These have been found to be relevant in the evaluation of viscoelastic effects in the steady flow through porous media. 相似文献