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1.
The detailed flow structure behind an impulsively started circular cylinder has been investigated experimentally. The Reynolds
number based on the steady state velocity and the diameter of the cylinder was 500 to 3,000. This work is unique in that unsteady
spatial velocities were measured simultaneously by a quantitative visualization technique — Laser Induced Photochemical Anemometry
(LIPA). The surface vorticity at g/q = π/2 and vorticity distribution behind the cylinder in the Lagrangian coordinates (i.e. coordinates fixed on the cylinder)
were calculated from the measured velocities. The surface vorticity shows in the early stage of flow development a close agreement
with the previous results obtained by analytical and numerical approaches. The large-field velocity and vorticity information
provides an insight into the formation process of the vortices downstream of the cylinder. In addition to the quantitative
information, the results of visualized flow pattern obtained by LIPA technique are also presented.
A preliminary version of this paper was presented at the Twelfth Symposium on Turbulence, University of Missouri-Rolla, Sept.
24–26, 1990 相似文献
2.
An exact solution is obtained for the problem of steady-state viscous incompressible flow under a pressure difference in the
gap between coaxial cylinders for the case where the inner cylinder rotates at a constant angular velocity. The solution differs
from the classical Couette-Poiseuille result by the presence of radial mass transfer, which provides for interaction between
the poloidal and azimuthal circulations. The flow rate is found to depend linearly on the angular velocity of rotation of
the inner cylinder.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 5, pp. 71–77, September–October, 2007. 相似文献
3.
The effect of flow intensification in small-sized vortex cells on the flow pattern in the near wake downstream of a cylinder
and the cylinder drag in laminar and turbulent flows is analyzed on the basis of a numerical simulation of the two-dimensional
steady-state flow past a circular cylinder with rotating cylindrical bodies built into the cylinder contour.
St. Petersburg, Saratov. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 88–96,
July–August, 2000.
The study was carried out with the support of the Russian Foundation for Basic Research (projects Nos. 99-01-01115 and 99-01-00772). 相似文献
4.
The problem of determination of the hydrodynamic characteristics of an ideal incompressible liquid moving with constant velocity
past a spherical body in an infinite circular cylinder is considered. It is assumed that the cylinder axis passes through
the mass center of the spherical body. The total liquid potential has been constructed both in spherical and cylindrical coordinate
systems. The hydrodynamic characteristics of the flow in the cylinder were researched based upon comparison with the corresponding
characteristics of the liquid flow of a spherical body in a boundless medium.
S. P. Timoshenko Mechanics Institute, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika,
Vol. 35, No. 6, pp. 27–31, June, 1999. 相似文献
5.
The flow velocity fluctuations in a gas laser are measured under non-self-maintained glow discharge conditions. Spectra of
the pulsating velocity signal on the frequency interval up to 2 kHz and the time dependence of the signal under glow and neutral
flow conditions for pure nitrogen, a mixture of nitrogen and helium, and a trial CO2-N2-He mixture are obtained. Deformation (due to the action of the discharge) of the spectra of the transverse velocity component
in the wake of a right circular cylinder is observed. In order to analyze the data obtained a model of the dynamic response
of the pulsating velocity is constructed and a model of the Kármán vortex street behind a body is generalized with allowance
for variations of the oscillation phase in the street.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 81–91, March–April, 2000.
The work was carried out with partial financial support from the Russian Foundation for Basic Research (projects Nos. 96-01-00372
and 99-01-01199). 相似文献
6.
M. Yu. Plotnikov 《Journal of Applied Mechanics and Technical Physics》2008,49(3):400-406
A supersonic flow around a cylinder is studied by the direct statistical Monte Carlo method in a wide range of rarefaction:
from regimes close to continuum to free-molecular flow. The effect of the accommodation coefficient on the flow near the cylinder
and on heat transfer between the gas and the cylinder is examined.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 64–72, May–June, 2008. 相似文献
7.
R. N. Bardakov V. V. Mitkin Yu. D. Chashechkin 《Journal of Applied Mechanics and Technical Physics》2007,48(6):840-851
The pattern of disturbances arising during the motion of a strip along a horizontal surface in a continuously stratified fluid
with identified upstream and attached internal waves, boundary layers, and edge singularities is calculated in the liner approximation.
The flow pattern behind a flat plate moving with a constant velocity in a continuously stratified fluid is studied with the
use of the optical schlieren technique; transformation of waves and finely structured elements of the flow with increasing
plate velocity is analyzed. The calculated and experimentally observed patterns of internal waves at low velocities are demonstrated
to be in good agreement.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 77–91, November–December, 2007. 相似文献
8.
V. M. Kuznetsov M. M. Kuznetsov 《Journal of Applied Mechanics and Technical Physics》1998,39(5):654-658
An analytical solution is obtained for the problem of acceleration of a body in a closed tube filled with a detonating mixture
of gases. It is assumed that the body enters the tube with a certain initial velocity sufficient for burning initiation in
an annular space between the body and tube surfaces. The effect of the mixture parameters, the shape and mass of the body,
and the integral dissipation of the total momentum and enthalpy of the flow on the finite values of the velocity and the acceleration
length is analyzed.
Central Aerohydrodynamic Institute, Zhukovskii 140160. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol.
39, No. 5, pp. 6–10, September–October, 1998. 相似文献
9.
Physical and mathematical modeling of a supersonic flow around a cylinder with a porous insert 总被引:1,自引:0,他引:1
I. A. Bedarev S. G. Mironov K. M. Serdyuk A. V. Fedorov V. M. Fomin 《Journal of Applied Mechanics and Technical Physics》2011,52(1):9-17
Results of numerical and experimental modeling of a supersonic flow (M∞ = 4.85) around a model of a streamwise-aligned cylinder with a cellular-porous insert permeable for the gas on the frontal
face of the cylinder are described. Experimental data on the influence of the pore structure and the length of the porous
cylindrical insert on the model drag, pressure on the frontal face of the cylinder, and flow pattern are obtained. Numerical
modeling includes solving Favre-averaged Navier-Stokes equations, which describe the motion of a viscous compressible heat-conducting
gas. The system is supplemented with a source term taking into account the drag of the porous body within the framework of
the continuum model of filtration. Data on pressure and velocity fields inside the porous body are obtained in calculations,
and the shape of an effective pointed body whose drag is equal to the drag of the model considered is determined. The calculated
results are compared with the measured data and schlieren visualization of the flow field. 相似文献
10.
This paper is concerned with a liquid metal flow driven by a rotating magnetic field inside a stationary cylinder. We consider
especially the secondary meridional flow during the time when the fluid spins up from rest. The developing flow is investigated
experimentally and by direct numerical simulations. The vertical profiles of the axial velocity are measured by means of the
ultrasound Doppler velocimetry. Evolving instabilities in the form of Taylor–G?rtler vortices have been observed just above
the instability threshold (Ta ≥ 1.5· Ta
cr). The rotational symmetry may survive over a distinct time even if a first Taylor–G?rtler vortex pair has been formed as
closed rings along the cylinder perimeter. The transition to a three-dimensional flow in the side layers results from the
advection or a precession and splitting of the Taylor–G?rtler vortex rings. The predictable behaviour of the Taylor–G?rtler
vortices disappears with increasing magnetic field strength. The numerical simulations agree very well with the flow measurements. 相似文献
11.
A. I. Usmanov 《Fluid Dynamics》1998,33(1):147-150
Supersonic flow past a cylindrical body with a system of transverse jets ejected from its surface at angles of attack α=60–120o is characterized by a complicated gasdynamic flow pattern [1]. The body surface is affected by both the oncoming flow and
the ejected jets which shield a portion of the surface from the external flow. This results in considerable transverse and
longitudinal pressure gradients appearing on the body surface. The experimental pressure distributions over a cylindrical
model with four transverse jets at a Mach number M=4 and α=60°, 90°, and 120° make it possible to study the specific features
of the flowfield and derive correlations for the "jet obstacle" dimensions.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 179–183, January–February,
1998. 相似文献
12.
V. V. Mitkin Yu. D. Chashechkin 《Journal of Applied Mechanics and Technical Physics》1999,40(5):811-819
Using various shadow methods of visualization for a stratified flow near a horizontal cylinder towed with constant velocity,
a new structural element of the flow, namely, the isolated high-gradient interlayers in the field of attached internal waves,
is identified. In their basic characteristic features, these layers may be viewed as those belonging to the class of inner
boundary layers which are the prevalent mechanism for formation of the fine structure of a continuously stratified medium.
The data on optical visualization are confirmed by direct measurements of the electrical conductivity.
Institute of Problems of Mechanics, Russian Academy of Sciences, Moscow 117526. Translated from Prikladnaya Mekhanika i Tekhnicheskaya
Fizika, Vol. 40, No. 5, pp. 40–50, September–October, 1999. 相似文献
13.
The turbulent fluid and particle interaction in the turbulent boundary layer for cross flow over a cylinder has been experimentally
studied. A phase-Doppler anemometer was used to measure the mean and fluctuating velocities of both phases. Two size ranges
of particles (30μm–60μm and 80μm–150μm) at certain concentrations were used for considering the effects of particle sizes
on the mean velocity profiles and on the turbulent intensity levels. The measurements clearly demonstrated that the larger
particles damped fluid turbulence. For the smaller particles, this damping effect was less noticeable. The measurements further
showed a delay in the separation point for two phase turbulent cross flow over a cylinder.
The project supported by the National Natural Science Foundation of China 相似文献
14.
The boundary layers developing on a single and two tandem circular cylinders were examined using multiple hot-film sensor
arrays for Re=2.4–5.1×104. Hot-wire and surface pressure measurements, and smoke-wire flow visualization were also made to better understand the flow
pattern and the evolution of the vortex street. The results show that, by use of the sensor arrays in conjunction with a bank
of constant-temperature anemometers, (i) the effects of the upstream cylinder on the boundary layer developing on the downstream
cylinder, (ii) the frequency of the vortex shedding, and (iii) the locations of flow separation and reattachment can be determined
non-intrusively and simultaneously. These measurement capabilities will provide a practical means for the characterization
and manipulation of unsteady flow phenomena.
Received: 27 October 1996 / Accepted: 13 February 1997 相似文献
15.
A. V. Kashevarov 《Fluid Dynamics》1994,29(1):33-37
The problem of the heat exchange of a circular cylinder in an incompressible flow at small Prandtl numbers Pr ≪ 1 is solved.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 43–48, January–February,
1994. 相似文献
16.
Wave motions in a fluid cylinder rotating about the axis are investigated within the framework of the linear theory. The cylinder
is assumed to be fairly long. This makes it possible to restrict attention to the study of the plane oscillation pattern.
The fluid is assumed to be ideal and incompressible. The models in which the fluid particles are confined by gravitational
(body) or/and capillary forces (surface stress forces) are considered. A mode analysis is carried out and the dispersion relations
are constructed. Traveling and steady-state waves on the surface of the fluid cylinder are investigated; qualitative effects
("wave inertia") are established.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 128–133, May–June, 1998.
The work was carried out with financial support from the Russian Foundation for Basic Research (project No. 96-01-00221).
An erratum to this article is available at . 相似文献
17.
I. N. Soldatov 《Journal of Applied Mechanics and Technical Physics》2008,49(2):167-171
The dispersion characteristics of gyroscopic waves in an incompressible liquid layer in a cavity of a rapidly rotating cylinder
are studied. It is shown that in a viscous incompressible liquid layer, an inertial wave can be represented as the sum of
six helical harmonics. The effects of the liquid viscosity and the ratio of the wave frequency to the angular velocity of
rotation of the cylinder on the real and imaginary parts of the wavenumber are studied.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 15–20, March–April, 2008. 相似文献
18.
The boundary-value problem of unsteady vortex flow of a viscous incompressible fluid in a cylindrical vessel with radial ribs
rotating at a variable angular velocity is solved using a finite-difference method. The results of the solution are used to
calculate the motion of a system of a solid body and a cavity filled with a liquid. The results are compared with available
experimental data.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 2, pp. 135–139, March–April, 2007. 相似文献
19.
Experimental studies of a plane jet impinging upon a small circular cylinder are conducted by hot-wire measurements. The
cylinder is located on the jet centerline within the potential-core region. The jet–cylinder interactions on the instability
shear layer frequency, the cylinder wake shedding frequency, and the induced self-sustained oscillation phenomenon are carefully
investigated. Test data indicate that the self-sustained flow oscillation is mainly generated by the resonant effect of the
flow between the jet exit and the cylinder. Its resonant frequency is found to vary linearly and exhibits jump-stage pattern
as a function of the distance between the jet exit and the cylinder. The feedback mechanism and the hydrodynamic instability
theorem are proposed to predict correctly the frequency jump position, wave number and the convection speed of the self-sustained
oscillating flow for different jet exit velocities.
Received: 15 July 1998/Accepted: 9 December 1998 相似文献
20.
V. L. Sennitskii 《Journal of Applied Mechanics and Technical Physics》2006,47(1):68-70
The ideal fluid flow due to fluid penetration through the boundary of an infinitely long solid cylinder in contact with a
solid wall is determined. A formula is derived according to which the force exerted by a finite-length part of the cylinder
on the wall is directed into the wall and can thus have an arbitrarily large absolute value.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 1, pp. 82–84, January–February, 2006. 相似文献