Distribution of Azimuthal Velocities in a Laminar Counter Vortex Flow

Zuykov, A. L.; Volshanik, V. V.; Orekhov, Genrikh

doi:10.22227/1997-0935.2013.5.150-161

Cited by 4 publications

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“…Within the zone of intensive flow energy dissipation with negative pressure in the steam-air core. Here, there is a cavitation due to flow separation (vortex) mainly occurring in vortices, at the boundary of shear of swirled currents (areas with high gradients of flow velocities tending to infinity [22,23,24]), and also at the boundary of a submerged axial jet in operation modes M.1-1 -1 or M.1-1A-1 and internal swirled current. The intensity of the cavitation manifestations will be the higher the deeper vacuum forms in the axial zone of the flow.…”

Section: Resultsmentioning

confidence: 99%

Pressure distribution and cavitation in counter-vortex flow energy dissipators of hydraulic spillways

Orekhov

2018

MATEC Web Conf.

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The article is devoted to the study of cavitation phenomena of counter-vortex flow energy dissipators that can be used in hydraulic spillways. The spillways providing the surface flow transitionn at hydraulic structures are equipped with energy dissipators of the discharged flow. An increase in the effective pressure on the hydropower project leads to an increase in the flow velocities and, hence , to an increase in the loads acting on the structures. One of such a manifestation is cavitation and cavitation erosion associated with it, which can lead to destruction of structures. The objective of the study consists in determining the cavitation characteristics of counter-vortex flow energy dissipators. The study was carried out by modeling using high-head physical models. The counter-vortex method of excess flow energy dissipation based on the work of viscous friction forces allows the flow energy to be dissipated in a very short part of the flow conductor system of the spillway. This feature of the counter-vortex flow energy dissipator imposes special requirements to the study of cavitation phenomena. The carried out studies resulted in obtaining the distribution of pressures lengthwise the flow conductor system of the energy dissipator with spiral swirls. The values of the cavitation coefficient and relative pressure at different points of the device are given. In the conclusions it is noted that the most dangerous part from the viewpoint of cavitation orrurence is the initial section of the flow energy dissipation chamber; cavitation due to flow separation and bubble cavitation occur within the flow and does not affect the structural elements; on a large-scale model working for 500 hours at pressures of up to 70 m cavitation erosion of the walls has not been detectd.

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Section: Resultsmentioning

confidence: 99%

Pressure distribution and cavitation in counter-vortex flow energy dissipators of hydraulic spillways

Orekhov

2018

MATEC Web Conf.

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“…The theoretical investigations performed are based on an approximate analytical solution of the Navier -Stokes's equations [15]. The solution itself is described in sufficient detail in our previous works, for example in [16][17][18][19][20], so the authors don't consider it necessary to stop here your attention on it. Let us now turn to the substance of this work.…”

Section: Methods Of Researchmentioning

confidence: 99%

Hydrodynamic structure of laminar flows with oppositely-swirled coaxial layers

Zuikov

Orekhov

2019

MATEC Web Conf.

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The article is devoted to the theoretical study of hydrodynamics of laminar flows with coaxial layers swirled in opposite directions and moving along the pipe. Such flows in a turbulent range have a wide practical application potential in technologies of dissipation of mechanical energy and mixing multiphase and heterogeneous media in microbiology, chemistry, ecology, heat engineering, power engineering, engine and rocket engineering. The article describes the tensor of viscous tangents (τii) and normal (σii) stresses. The questions of stability of flow according to the Rayleigh (Ra) and Richardson (Ri) criteria are considered. Calculation formulas and graphs of radial-axial distributions of viscous stress components, local stability zones are given, the point of “crisis and decay of the flow” or “vortex breakdown” is indicated. The solutions are obtained in the form of Fourier-Bessel series. The analysis of the hydrodynamic structure of the flow is made.

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“…In the article presents the results of theoretical studies of the structure of counter-vortex flows based on recent publications [10][11][12][13][14][15]. In these publications in the cylindrical coordinate system r -x ( Fig.…”

Section: Methods Of Researchmentioning

confidence: 99%

“…Decisions of the system of equations (2) with the boundary conditions (3) are given in the above publications [10][11][12][13][14][15] which in chronological order improve and complement each other. But in general, the most comprehensive solutions for today are the radial-axial distributions of azimuthal and axial velocities given in monograph [10] in the form of Fourier -Bessel's series or the products of Fourier -Bessel's series…”

Section: Distributions Of Flow Velocitiesmentioning

confidence: 99%

Structure of laminar flows with oppositely-rotating coaxial layers

2018

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The article is devoted to the theoretical study of laminar flows with the coaxial layers rotating in opposite directions moving along the pipe. These flows have a wide practical application potential in technologies of mixing multiphase and heterogeneous media in microbiology, chemistry, ecology, heat engineering, power engineering, civil engineering and engine and rocket science. Such flows have a complicated three-dimensional structure. The theoretical model of the test flow is based on the Navier – Stokes's equations and Fourier – Bessel's method of expansion of differential equations. The article presents the formulas and graphs showing the radial-axial distributions of tangential, axial and radial flow velocities, stream functions and viscous vortex components. The authors made the theoretical analysis of the kinematic structure of such flows.

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Distribution of Azimuthal Velocities in a Laminar Counter Vortex Flow

Cited by 4 publications

References 0 publications

Pressure distribution and cavitation in counter-vortex flow energy dissipators of hydraulic spillways

Pressure distribution and cavitation in counter-vortex flow energy dissipators of hydraulic spillways

Hydrodynamic structure of laminar flows with oppositely-swirled coaxial layers

Structure of laminar flows with oppositely-rotating coaxial layers

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