Higher approximations in the problem of axisymmetric jet flow on a circular cylinder

1979 ◽  
Vol 14 (5) ◽  
pp. 652-657
Author(s):  
N. N. Kortikov ◽  
I. B. Novikova
Keyword(s):  
Circular Cylinder ◽  
Jet Flow ◽  
Axisymmetric Jet

Simulation of particle dispersion in an axisymmetric jet

1988 ◽  
Vol 186 ◽  
pp. 199-222 ◽  
Author(s):  
J. N. Chung ◽  
T. R. Troutt
Keyword(s):  
Mixing Layer ◽  
Jet Flow ◽  
Particle Dispersion ◽  
Vortex Rings ◽  
Local Flow ◽  
Discrete Vortex ◽  
Turbulent Mixing Layer ◽  
Axisymmetric Jet ◽  
Free Jet ◽  
Global And Local

Particle dispersion in an axisymmetric jet is analysed numerically by following particle trajectories in a jet flow simulated by discrete vortex rings. Important global and local flow quantities reported in experimental measurements are successfully simulated by this method.The particle dispersion results demonstrate that the extent of particle dispersion depends strongly on γτ, the ratio of particle aerodynamic response time to the characteristic time of the jet flow. Particles with relatively small γτ values are dispersed at approximately the fluid dispersion rate. Particles with large γτ values are dispersed less than the fluid. Particles at intermediate values of γτ may be dispersed faster than the fluid and actually be flung outside the fluid mixing region of the jet. This result is in agreement with some previous experimental observations. As a consequence of this analysis, it is suggested that there exists a specific range of intermediate γτ at which optimal dispersion of particles in the turbulent mixing layer of a free jet may be achieved.

Suppression of vortex-induced vibration of a circular cylinder by a passive-jet flow control

2020 ◽  
Vol 199 ◽  
pp. 104119 ◽  
Author(s):  
Wen-Li Chen ◽  
Guan-Bin Chen ◽  
Feng Xu ◽  
Ye-wei Huang ◽  
Dong-Lai Gao ◽  
...  
Keyword(s):  
Circular Cylinder ◽  
Flow Control ◽  
Jet Flow ◽  
Vortex Induced Vibration

623 Vibration Behavior of a Circular Cylinder subjected to Jet-Flow from a Narrow Gap in the Vicinity of Wall using CFD

2005 ◽  
Vol 2005.80 (0) ◽  
pp. _6-51_-_6-52_
Author(s):  
Kyousuke KAWABE ◽  
Katsuhisa FUJITA
Keyword(s):  
Circular Cylinder ◽  
Jet Flow ◽  
Narrow Gap ◽  
Vibration Behavior

Passive Jet Flow Control Method for Suppressing Unsteady Vortex Shedding from a Circular Cylinder

2017 ◽  
Vol 30 (1) ◽  
pp. 04016063 ◽  
Author(s):  
Wen-Li Chen ◽  
Xiangjun Wang ◽  
Feng Xu ◽  
Hui Li ◽  
Hui Hu
Keyword(s):  
Circular Cylinder ◽  
Flow Control ◽  
Vortex Shedding ◽  
Control Method ◽  
Jet Flow

Suppression of Unsteady Vortex Shedding From a Circular Cylinder by Using a Passive Jet Flow Control Method

2014 ◽  
Author(s):  
Wenli Chen ◽  
Hui Li ◽  
Hui Hu
Keyword(s):  
Circular Cylinder ◽  
Flow Control ◽  
Stagnation Point ◽  
Vortex Shedding ◽  
Control Method ◽  
Aerodynamic Force ◽  
Jet Flow ◽  
Wake Flow ◽  
Cylinder Model ◽  
Rear Stagnation Point

A passive jet flow control method was employed to suppress the unsteady vortex shedding from a circular cylinder at the Reynolds number level of Re = (0.18∼1.1)×105. The passive jet flow control was achieved by blowing jets from the holes near the rear stagnation point of the cylinder, which are connected to the in-take holes located near the front stagnation point through channels embedded inside the cylinder. Since a part of the oncoming flow would inhale into the in-take holes, flow through the embedded channels, and blow out from the holes near the rear stagnation point to suppress/manipulate the alternating vortex shedding in the wake flow behind the circular cylinder, the present passive jet flow control method does not require any additional energy inputs for the flow control. In the present study, the aerodynamic force (i.e., both lift and drag) acting the circular cylinder model with and without the passive jet flow control were compared quantitatively at different Reynolds numbers (i.e., different inlet mean speed). It was found that, in addition to almost eliminating the fluctuations of the lift forces acting on the cylinder, the passive jet flow control method was also found to reduce the mean drag acting on the cylinder model greatly. The instantaneous vorticity distributions and corresponding streamline patterns were used to reveal the underlying physics about why and how the passive jet flow control method can be used to suppress the alternating vortex shedding and induce a symmetrical wake pattern behind the cylinder model.

Vibration Behavior of a Circular Cylinder subjected to Jet-Flow, from a Narrow Gap in the Vicinity of Wall

2004 ◽  
Vol 2004.7 (0) ◽  
pp. 121-122
Author(s):  
Kyousuke KAWABE ◽  
Katsuhisa FUJITA
Keyword(s):  
Circular Cylinder ◽  
Jet Flow ◽  
Narrow Gap ◽  
Vibration Behavior

The effect of nozzle geometry on the turbulence evolution in an axisymmetric jet flow: A focus on fractals

2020 ◽  
Vol 550 ◽  
pp. 124145
Author(s):  
Yongwon Seo ◽  
Haeng Sik Ko ◽  
Sangyoung Son
Keyword(s):  
Jet Flow ◽  
Nozzle Geometry ◽  
Axisymmetric Jet

Unstable waves on an axisymmetric jet column

1974 ◽  
Vol 65 (3) ◽  
pp. 541-560 ◽  
Author(s):  
G. E. Mattingly ◽  
C. C. Chang
Keyword(s):  
Flow Field ◽  
Shear Layer ◽  
Stability Theory ◽  
Jet Flow ◽  
Jet Flows ◽  
Water Tank ◽  
Mean Velocity ◽  
Core Diameter ◽  
Potential Core ◽  
Axisymmetric Jet

The growth of infinitesimal disturbances on an axisymmetric jet column is investigated theoretically and experimentally. The theoretical analysis is based upon inviscid stability theory, wherein axisymmetric, helical and double helical disturbances are considered from the spatial reference frame. In the jet flow field near the source, the mean velocity profile is observed to have a potential core and a thin, but finite, shear layer between the potential core and the quiescent ambient fluid. With downstream distance, the potential core diameter decreases and the shear-layer thickness increases. To incorporate these variations into the theory, a quasi-uniform assumption is adopted, whereby successive velocity profiles are analysed individually throughout the region in the jet flow where disturbances are observed to be small. The results of the theory indicate that initially, in the jet flow where the shear layer is thin and the potential core is larger, all disturbances considered are unstable. The dominant disturbance in the jet is an axisymmetric one. However, further downstream in the jet, where the half-breadth thickness of the shear layer is 55% of the potential core radius, a helical disturbance is found to dominate the axisymmetric and double helical modes. Nowhere in the jet flow field examined was the double helical disturbance found to be dominant. The cross-stream distributions of velocity and vorticity for the dominant disturbance modes are presented according to the spatial stability theory.The downstream development of the jet column and the characteristics of the disturbances amplifying on it were also studied in a water tank. No artificial stimulation of any particular disturbance was used. The experimental results show good agreement with the results of the theory in the region where the disturbances are small. However, conclusive confirmation of the switch in the hierarchy of dominant disturbances was not found. Half of the time the disturbance observed experimentally exhibits an axisymmetric character and the other half a helical one. This apparently is due to the similar spatial amplification rates experienced by both of these disturbance modes. It is concluded that this switching of dominant modes is, in large part, responsible for (i) the well-known natural drifting of disturbance characteristics in jet flows, and (ii) the wide variety of observations made in previous jet experiments.

scholarly journals Axisymmetric Jet Flow Issuing from a Circular Nozzle

1974 ◽  
Vol 40 (336) ◽  
pp. 2190-2196
Author(s):  
Keiji HATTA ◽  
Tsutomu NOZAKI
Keyword(s):  
Jet Flow ◽  
Axisymmetric Jet ◽  
Circular Nozzle
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