共查询到10条相似文献,搜索用时 125 毫秒
1.
G. A. Ruev A. V. Fedorov V. M. Fomin 《Journal of Applied Mechanics and Technical Physics》2010,51(3):308-316
The evolution of the initially disturbed mixing layer of two gases of different densities under the action of an incident
shock wave, shock waves reflected from the end face, compression and expansion waves is studied in a two-dimensional unsteady
approximation on the basis of the previously formulated mathematical model of mechanics of a two-velocity two-temperature
mixture of gases. Problems of wave interaction with a sinusoidally disturbed diffusion layer are solved numerically. It is
shown that the calculated width of the mixing region is in good agreement with experimental data. 相似文献
2.
A. A. Maslov A. N. Kudryavtsev S. G. Mironov T. V. Poplavskaya I. S. Tsyryulnikov 《Journal of Applied Mechanics and Technical Physics》2007,48(3):368-374
Direct numerical simulations of the evolution of disturbances in a viscous shock layer on a flat plate are performed for a
free-stream Mach number M
∞ = 21 and Reynolds number Re
L = 1.44 · 105. Unsteady Navier-Stokes equations are solved by a high-order shock-capturing scheme. Processes of receptivity and instability
development in a shock layer excited by external acoustic waves are considered. Direct numerical simulations are demonstrated
to agree well with results obtained by the locally parallel linear stability theory (with allowance for the shock-wave effect)
and with experimental measurements in a hypersonic wind tunnel. Mechanisms of conversion of external disturbances to instability
waves in a hypersonic shock layer are discussed.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 84–91, May–June, 2007. 相似文献
3.
V. S. Sazonov 《Fluid Dynamics》2012,47(2):239-253
Parameters of emitting shock waves in gases are investigated in the limiting case when there is no screening of emission from
the shock front by the precursory layer. The one-dimensional quasi-steady-state formulation of the problem with deceleration
of high-speed gas flow against a plane fixed obstacle under conditions of strong emission is given. The case of the shock
waves of large optical thickness is analytically considered over a wide range of variation of the obstacle reflectivity. The
parameters of emitting shock waves generated in experiments in shock tubes in the inert argon gas are estimated using the
methods developed and compared with the measurement results. The shock “adiabats” of optically thick shock waves are considered
with allowance for the radiation energy losses. The calculations are carried out for aluminium plasma. 相似文献
4.
The propagation of shock waves in a medium with a nonuniform distribution of the parameters is the subject of recently published
research [1–3]. The present paper deals with the problem of the gas flow ahead of the forward point of a blunt body moving
at supersonic speed in air with variable parameters. The chemical reaction processes behind the shock front are taken into
account. As a result of numerical calculations by the method of characteristics with isolation of the forward shock the time-dependent
position of the shock front and the distributions of the composition and gas dynamic parameters in the shock layer are found.
Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 170–172, November–December, 1986. 相似文献
5.
The transition from regular to Mach interaction is investigated in connection with the interaction of two plane weak or moderate
shock waves of different intensity in a two-phase gas-liquid medium over the entire range of gas contents. A nonmonotonic
dependence of the transition limit and the flow parameters on the gas content is detected. The investigation extends the results
of [1] corresponding to the reflection of a shock wave from a wall. At intermediate gas contents in the case of opposing shock
waves, analogous to the normal reflection of a shock wave from a solid wall, the results are in agreement with [2]. In the
case of weak shock waves non-linear asymptotic expansions [3] are employed. In the extreme cases of single-phase media the
results coincide with the findings of [3, 4].
Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 172–174, November–December, 1986. 相似文献
6.
The interaction between a normally impinging shock wave and the boundary layer on a plate with slip is studied in the neighborhood
of the leading edge using various experimental methods, including special laser technology, to visualize the supersonic conical
gas flows. It is found that in the “non-free” interaction, when the leading edge impedes the propagation of the boundary layer
separation line upstream, the structure of the disturbed flow is largely identical to that in the developed “free” interaction,
but with higher parameter values and gradients in the leading part of the separation zone. The fundamental property of developed
separation flows, namely, coincidence of the values of the pressure “plateau” in the separation zone and the pressure behind
the oblique shock above the separation zone of the turbulent boundary layer, is conserved.
Moscow. e-mail: ostap@inmech.msu.su. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3,
pp. 57–69, May–June, 2000.
The work was carried out with financial support from the Russian Foundation for Basic Research (project No. 97-01-00099). 相似文献
7.
This paper presents the results of an experimental study of the unsteady nature of a hypersonic separated turbulent flow.
The nomimal test conditions were a freestream Mach number of 7.8 and a unit Reynolds number of 3.5×107/m. The separated flow was generated using finite span forward facing steps. An array of flush mounted high spatial resolution
and fast response platinum film resistance thermometers was used to make multi-channel measurements of the fluctuating surface
heat trtansfer within the separated flow. Conditional sampling analysis of the signals shows that the root of separation shock
wave consists of a series of compression wave extending over a streamwise length about one half of the incoming boundary layer
thickness. The compression waves converge into a single leading shock beyond the boundary layer. The shock structure is unsteady
and undergoes large-scale motion in the streamwise direction. The length scale of the motion is about 22 percent of the upstream
influence length of the separation shock wave. There exists a wide band of frequency of oscillations of the shock system.
Most of the frequencies are in the range of 1–3 kHz. The heat transfer fluctuates intermittently between the undisturbed level
and the disturbed level within the range of motion of the separation shock wave. This intermittent phenomenon is considered
as the consequence of the large-scale shock system oscillations. Downstream of the range of shock wave motion there is a separated
region where the flow experiences continuous compression and no intermittency phenomenon is observed.
The project supported by National Natural Science Foundation of China 相似文献
8.
Characteristics of unsteady type IV shock/shock interaction 总被引:1,自引:0,他引:1
Characteristics of the unsteady type IV shock/shock interaction of hypersonic blunt body flows are investigated by solving
the Navier–Stokes equations with high-order numerical methods. The intrinsic relations of flow structures to shear, compression,
and heating processes are studied and the physical mechanisms of the unsteady flow evolution are revealed. It is found that
the instantaneous surface-heating peak is caused by the fluid in the “hot spot” generated by an oscillating and deforming
jet bow shock (JBS) just ahead of the body surface. The features of local shock/boundary layer interaction and vortex/boundary
layer interaction are clarified. Based on the analysis of flow evolution, it is identified that the upstream-propagating compression
waves are associated with the interaction of the JBS and the shear layers formed by a supersonic impinging jet, and then the
interaction of the freestream bow shocks and the compression waves results in entropy and vortical waves propagating to the
body surface. Further, the feedback mechanism of the inherent unsteadiness of the flow field is revealed to be related to
the impinging jet. A feedback model is proposed to reliably predict the dominant frequency of flow evolution. The results
obtained in this study provide physical insight into the understanding of the mechanisms relevant to this complex flow. 相似文献
9.
H. R. Pakzad 《Shock Waves》2011,21(4):357-365
Dust acoustic shock waves of the Korteweg-de Vries–Burgers (KdV–Burgers) equation and the modified Korteweg-de Vries–Burgers
(MKdV–Burgers) equation are studied in strongly coupled dusty plasmas containing nonthermal ions and Boltzmann-distributed
electrons. The effects of important parameters, such as nonthermal parameter, relative temperature, relative density and dust
particles viscosity, on the properties of shock waves are discussed. 相似文献
10.
A. N. Kudryavtsev S. G. Mironov T. V. Poplavskaya I. S. Tsyryul’nikov 《Journal of Applied Mechanics and Technical Physics》2006,47(5):617-627
The evolution of disturbances in a hypersonic viscous shock layer on a flat plate excited by slow-mode acoustic waves is considered
numerically and experimentally. The parameters measured in the experiments performed with a free-stream Mach number M
∞ = 21 and Reynolds number Re
L = 1.44 · 105 are the transverse profiles of the mean density and Mach number, the spectra of density fluctuations, and growth rates of
natural disturbances. Direct numerical simulation of propagation of disturbances is performed by solving the Navier-Stokes
equations with a high-order shock-capturing scheme. The numerical and experimental data characterizing the mean flow field,
intensity of density fluctuations, and their growth rates are found to be in good agreement. Possible mechanisms of disturbance
generation and evolution in the shock layer at hypersonic velocities are discussed.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 5, pp. 3–15, September–October, 2006. 相似文献