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Volshanik, V. V.; Karelin, V. Ya.; Zuikov, A. L.; Orekhov, Genrikh

doi:10.1023/a:1017520608741

Cited by 4 publications

(3 citation statements)

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“…It must be said here that a counter-vortex flow is an artificially created flow in which oppositely swirling layers of fluid or gas interact in a circular cylindrical chamber. Studies on physical models of various scales and in the prototype have shown that 95-98% of the total flow kinetic energy dissipation can occur at a length of up to 10-15 radii of a circular cylindrical tube [19,20]. In this respect, this method of flow energy dissipation is unique and deserves a detailed study of all parameters of the counter-vortex flow.…”

Section: Introductionmentioning

confidence: 99%

Circumferential velocities in laminar and turbulent counter-vortex flow

Orekhov

2023

E3S Web of Conf.

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Knowledge of the parameters of fluid movement is essential in the designing and operating various technological processes in various technical applications. These processes play a special role in hydro engineering, where the structures of water works are directly subjected to static and dynamic forces from the side of the water flow. The operation of hydraulic turbines, spillway and water transport systems, and other hydraulic structures is directly connected with understanding the behavior of a fluid in various regimes of movement. This report is devoted to the study of a special type of fluid and gas flow, which is called counter-vortex flow. The report compares the results of the distribution of circumferential velocities with a laminar and turbulent pattern of fluid movement. The results of the laminar flow regime were obtained using a mathematical model, and the turbulent regime on a physical model using laser technologies. Such a comparison allows one to assess two approaches in determining the kinematic structures of a complicated flow. The parameters for the viscous fluid laminar flow were determined based on the traditional system of Navier-Stokes equations by determining the dependence of the circumferential component of the total velocity at the given initial circulations and angular flow velocity. A physical model was made and equipped with a set of measuring equipment to obtain the distribution of velocities in the turbulent flow. The comparison showed that the distributions of velocities for the considered flow regimes depending on the channel radius have close coincidence. In contrast, the transformation length-wise of the active zone of the flow is significant.

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Section: Introductionmentioning

confidence: 99%

Circumferential velocities in laminar and turbulent counter-vortex flow

Orekhov

2023

E3S Web of Conf.

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“…Suggestions for the use of interacting flows were prompted by practice requirements. This is primarily the flow energy dissipation in high-head hydraulic systems, mixing of two-phase flows consisting of liquids and gases [14,15]. The method of flow energy dissipation using the interaction of flows (jets) is based on the idea of dividing the initial flow into parts and creating conditions for the mutual energy dissipation of individual flow parts with their subsequent connection.…”

Section: Introductionmentioning

confidence: 99%

Flow kinematics with oppositely rotating coaxial layers

Orekhov

2019

E3S Web Conf.

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In modern technological processes, liquid and gas flows play an important role. This is especially mostly evident in hydraulic engineering and hydropower construction when designing the highly efficient hydraulic turbines, various spillway systems and other elements of layout patterns of structures. When designing and constructing such facilities, it is necessary to know the characteristics of the flows to be passed through these structures in order to correctly take into account the various types of impacts from the flow: pressure pulsations, cavitation and erosion due to cavitation, wave formation and abrasive wear. When designing high-head spillway structures, special attention is paid to the presence of excess energy from the stream entering the lower pool, which requires special measures to dissipate it. Nowadays, in the practice of construction of hydraulic structures, swirled flows are used including those with oppositely rotating layers. This type of flow creates a number of effects that allow one to radically solve the problems of energy dissipation of high-velocity flows. The report presents the results of studies of a complicated flow formed by oppositely rotating coaxially arranged layers of liquid made by a physical method. The description of the experimental stand for the model studies of such flows is given. The basic parameters of the installation, the principle of operation of the recording equipment and its main characteristics are given. The results of model studies in the form of distribution of the components of the flow velocity along the cross section of the flow conductor and its length are given.

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“…The transition to high heads requires new approaches to the study of the phenomena associated with high-velocity streams and development of fundamentally new types of currents and designs of the energy dissipators of flows to be discharged This approach forms new technological solutions in hydraulic engineering. One of them is the method of flow energy dissipation by means of counter-vortex dissipators based on of viscous friction forces of oppositely directed circulation currents [17]. This feature of the counter-vortex dissipator imposes special requirement on the study of cavitation phenomena taking place during its operation.…”

Section: Introductionmentioning

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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Cited by 4 publications

References 0 publications

Circumferential velocities in laminar and turbulent counter-vortex flow

Circumferential velocities in laminar and turbulent counter-vortex flow

Flow kinematics with oppositely rotating coaxial layers

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

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