Lidar observations of turbulent vortex shedding by an isolated topographic feature

1996 ◽  
Vol 80 (1-2) ◽  
pp. 95-108 ◽  
Author(s):  
William P. Hooper ◽  
Jeffrey E. James ◽  
Richard J. Lind
Keyword(s):  
Vortex Shedding ◽  
Topographic Feature ◽  
Turbulent Vortex ◽  
Turbulent Vortex Shedding ◽  
Lidar Observations

Computation of turbulent vortex shedding

2005 ◽  
Vol 37 (5) ◽  
pp. 408-425 ◽  
Author(s):  
B. A. Younis ◽  
V. P. Przulj
Keyword(s):  
Vortex Shedding ◽  
Turbulent Vortex ◽  
Turbulent Vortex Shedding

Turbulent vortex streets and the entrainment mechanism of the turbulent wake

1974 ◽  
Vol 62 (1) ◽  
pp. 11-31 ◽  
Author(s):  
Demosthenes D. Papailiou ◽  
Paul S. Lykoudis
Keyword(s):  
Vortex Shedding ◽  
Reynolds Numbers ◽  
Turbulent Wake ◽  
Vortex Street ◽  
Experimental Measurements ◽  
Formation Region ◽  
Turbulent Vortex ◽  
Geometrical Characteristics ◽  
Vortex Streets ◽  
Longitudinal Distance

The results of an experimental investigation of a turbulent vortex street in the range 103 [lsim ] Re [lsim ] 2 × 104 are presented. The vortex street was created by the motion of a circular cylinder in a motionless fluid (mercury). Photographs obtained showed that the turbulent street, created by the vortex shedding behind the cylinder, persisted at longer downstream distances and higher Reynolds numbers than previously reported in the literature. A theory was developed to account for the experimental measurements pertaining to the change of the geometrical characteristics, h (distance between the two rows of vortices) and α (longitudinal distance between two consecutive vortices on the same row), of the street in the downstream direction. The implications of the structure of the vortex street on the entrainment mechanism of the turbulent wake are discussed. Some observations of the flow in the formation region of the vortices are discussed in relation to existing work.

Evolution of unstable system.

2015 ◽  
Vol 9 (3) ◽  
pp. 2487-2502 ◽  
Author(s):  
Igor V. Lebed
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Flow ◽  
Stable Solution ◽  
The State ◽  
Unstable System ◽  
Unstable Flow ◽  
Unstable Solutions ◽  
Vortex Shedding Modes ◽  
Hydrodynamics Equations

Scenario of appearance and development of instability in problem of a flow around a solid sphere at rest is discussed. The scenario was created by solutions to the multimoment hydrodynamics equations, which were applied to investigate the unstable phenomena. These solutions allow interpreting Stokes flow, periodic pulsations of the recirculating zone in the wake behind the sphere, the phenomenon of vortex shedding observed experimentally. In accordance with the scenario, system loses its stability when entropy outflow through surface confining the system cannot be compensated by entropy produced within the system. The system does not find a new stable position after losing its stability, that is, the system remains further unstable. As Reynolds number grows, one unstable flow regime is replaced by another. The replacement is governed tendency of the system to discover fastest path to depart from the state of statistical equilibrium. This striving, however, does not lead the system to disintegration. Periodically, reverse solutions to the multimoment hydrodynamics equations change the nature of evolution and guide the unstable system in a highly unlikely direction. In case of unstable system, unlikely path meets the direction of approaching the state of statistical equilibrium. Such behavior of the system contradicts the scenario created by solutions to the classic hydrodynamics equations. Unstable solutions to the classic hydrodynamics equations are not fairly prolonged along time to interpret experiment. Stable solutions satisfactorily reproduce all observed stable medium states. As Reynolds number grows one stable solution is replaced by another. They are, however, incapable of reproducing any of unstable regimes recorded experimentally. In particular, stable solutions to the classic hydrodynamics equations cannot put anything in correspondence to any of observed vortex shedding modes. In accordance with our interpretation, the reason for this isthe classic hydrodynamics equations themselves.

Some modeling issues on trailing-edge vortex shedding

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 787-793
Author(s):  
Wei Ning ◽  
Li He
Keyword(s):  
Vortex Shedding ◽  
Trailing Edge ◽  
Edge Vortex
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