Hydrodynamic structure of laminar flows with oppositely-swirled coaxial layers

Andrey Zuikov,Genrikh Orekhov,S Kudryavtsev,C Yoo,A Zhussupbekov

doi:10.1051/matecconf/201926502022

Andrey Zuikov, Genrikh Orekhov + Show 3 more

Open Access

https://doi.org/10.1051/matecconf/201926502022

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Abstract

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.

Highlights

This paper describes the viscous stress tensor and local stability zones of liquid flow, in which concurrent coaxial layers swirl in opposite directions (Fig. 1)
Both properties of such flows have a great potential for practical use [4, 7]: the first - in technologies involving the mixing of heterogeneous and multiphase media in microbiology, chemistry, ecology, heat engineering, power engineering, engine and rocketengineering; the second - to dissipate the mechanical energy of the flow of liquid or gas, for example, in high-pressure hydraulic spillways [1, 2, 8, 9] or for suppressing the noise of aircraft engines, propellers of ships
The effective development of these technologies is impossible without knowledge of the hydrodynamics of such flows

Summary

Introduction

This paper describes the viscous stress tensor and local stability zones of liquid flow, in which concurrent coaxial layers swirl in opposite directions (Fig. 1). The relevance of the topic is related to the fact that the flows with oppositely swirling coaxial layers in the turbulent range are characterized by intensive mixing (diffusion) and quenching (dissipation) of the mechanical energy of the moving viscous media Both properties of such flows have a great potential for practical use [4, 7]: the first - in technologies involving the mixing of heterogeneous and multiphase media in microbiology, chemistry, ecology, heat engineering, power engineering, engine and rocketengineering; the second - to dissipate the mechanical energy of the flow of liquid or gas, for example, in high-pressure hydraulic spillways [1, 2, 8, 9] or for suppressing the noise of aircraft engines, propellers of ships. Such flows arise in cyclones and draft tubes behind Francis hydraulic turbines in non-optimal operation modes [10,11,12,13,14]

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