206 Experimental study of a circular cylinder with tangential blowing in a flow field

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

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Development of a flow field structure in the vicinity of a circular cylinder in the presence of a laminar-turbulent transition

High Temperature ◽

10.1007/bf02755926 ◽

2000 ◽

Vol 38 (5) ◽

pp. 732-741

Author(s):

V. A. Bashkin ◽

I. V. Egorov ◽

M. V. Egorova ◽

D. V. Ivanov

Keyword(s):

Circular Cylinder ◽

Flow Field ◽

Field Structure ◽

Turbulent Transition ◽

Laminar Turbulent Transition

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Discussion of “Experimental Study of the Flow Field over Bottom Intake Racks” by Maurizio Righetti and Stefano Lanzoni

Journal of Hydraulic Engineering ◽

10.1061/(asce)hy.1943-7900.0000007 ◽

2009 ◽

Vol 135 (10) ◽

pp. 865-865 ◽

Cited By ~ 1

Author(s):

Willi H. Hager

Keyword(s):

Experimental Study ◽

Flow Field ◽

Bottom Intake

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Aeroacoustic Simulation around a Circular Cylinder by the Equations Split for Incompressible Flow Field and Acoustic Field

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.71.2694 ◽

2005 ◽

Vol 71 (711) ◽

pp. 2694-2701 ◽

Cited By ~ 1

Author(s):

Yoshihiro KATO ◽

Igor MEN'SHOV ◽

Yoshiaki NAKAMURA

Keyword(s):

Circular Cylinder ◽

Flow Field ◽

Acoustic Field ◽

Incompressible Flow ◽

Aeroacoustic Simulation

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The drag-adjoint field of a circular cylinder wake at Reynolds numbers 20, 100 and 500

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.323 ◽

2013 ◽

Vol 730 ◽

pp. 145-161 ◽

Cited By ~ 27

Author(s):

Qiqi Wang ◽

Jun-Hui Gao

Keyword(s):

Circular Cylinder ◽

Flow Field ◽

Unsteady Flow ◽

Numerical Solutions ◽

Reynolds Numbers ◽

Adjoint Equations ◽

Cylinder Wake ◽

Near Wake ◽

Navier Stokes Equation ◽

D 20

AbstractThis paper analyses the adjoint solution of the Navier–Stokes equation. We focus on flow across a circular cylinder at three Reynolds numbers, ${\mathit{Re}}_{D} = 20, 100$ and $500$. The quantity of interest in the adjoint formulation is the drag on the cylinder. We use classical fluid mechanics approaches to analyse the adjoint solution, which is a vector field similar to a flow field. Production and dissipation of kinetic energy of the adjoint field is discussed. We also derive the evolution of circulation of the adjoint field along a closed material contour. These analytical results are used to explain three numerical solutions of the adjoint equations presented in this paper. The adjoint solution at ${\mathit{Re}}_{D} = 20$, a viscous steady state flow, exhibits a downstream suction and an upstream jet, the opposite of the expected behaviour of a flow field. The adjoint solution at ${\mathit{Re}}_{D} = 100$, a periodic two-dimensional unsteady flow, exhibits periodic, bean-shaped circulation in the near-wake region. The adjoint solution at ${\mathit{Re}}_{D} = 500$, a turbulent three-dimensional unsteady flow, has complex dynamics created by the shear layer in the near wake. The magnitude of the adjoint solution increases exponentially at the rate of the first Lyapunov exponent. These numerical results correlate well with the theoretical analysis presented in this paper.

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