VORTEX FORMATION IN A LOW ASPECT RATIO SYNTHETIC JET

2020 ◽  
Vol 27 (2) ◽  
pp. 117-141
Author(s):  
Jyoti Gupta ◽  
S. S. G. Satish ◽  
Arun K. Saha
Keyword(s):  
Aspect Ratio ◽  
Vortex Formation ◽  
Synthetic Jet ◽  
Low Aspect Ratio

scholarly journals The influence of edge undulation on vortex formation for low-aspect-ratio propulsors

2019 ◽  
Vol 883 ◽  
Author(s):  
Frieder Kaiser ◽  
Jochen Kriegseis ◽  
David E. Rival
Keyword(s):  
Aspect Ratio ◽  
Vortex Formation ◽  
Low Aspect Ratio ◽  
Image Position

scholarly journals Role of the tip vortex in the force generation of low-aspect-ratio normal flat plates

2007 ◽  
Vol 581 ◽  
pp. 453-468 ◽  
Author(s):  
MATTHEW J. RINGUETTE ◽  
MICHELE MILANO ◽  
MORTEZA GHARIB
Keyword(s):  
Aspect Ratio ◽  
Vortex Formation ◽  
Three Dimensional ◽  
Unsteady Motion ◽  
Tip Vortex ◽  
Flat Plates ◽  
Low Aspect Ratio ◽  
Start Up ◽  
Image Velocimetry

We investigate experimentally the force generated by the unsteady vortex formation of low-aspect-ratio normal flat plates with one end free. The objective of this study is to determine the role of the free end, or tip, vortex. Understanding this simple case provides insight into flapping-wing propulsion, which involves the unsteady motion of low-aspect-ratio appendages. As a simple model of a propulsive half-stroke, we consider a rectangular normal flat plate undergoing a translating start-up motion in a towing tank. Digital particle image velocimetry is used to measure multiple perpendicular sections of the flow velocity and vorticity, in order to correlate vortex circulation with the measured plate force. The three-dimensional wake structure is captured using flow visualization. We show that the tip vortex produces a significant maximum in the plate force. Suppressing its formation results in a force minimum. Comparing plates of aspect ratio six and two, the flow is similar in terms of absolute distance from the tip, but evolves faster for aspect ratio two. The plate drag coefficient increases with decreasing aspect ratio.

Vortex formation and saturation for low-aspect-ratio rotating flat-plate fins

2011 ◽  
Vol 52 (2) ◽  
pp. 441-462 ◽  
Author(s):  
Adam C. DeVoria ◽  
Matthew J. Ringuette
Keyword(s):  
Aspect Ratio ◽  
Flat Plate ◽  
Vortex Formation ◽  
Low Aspect Ratio

Unsteady RANS Simulations of a Highly Loaded Low Aspect Ratio Compressor Stator Cascade With Active Flow Control

2010 ◽  
Author(s):  
Christoph Gmelin ◽  
Mathias Steger ◽  
Frank Thiele ◽  
Andre´ Huppertz ◽  
Marius Swoboda
Keyword(s):  
Aspect Ratio ◽  
Flow Control ◽  
Active Flow Control ◽  
Pressure Rise ◽  
Suction Side ◽  
Synthetic Jet ◽  
Compressor Cascade ◽  
Low Aspect Ratio ◽  
Rans Simulations ◽  
Highly Loaded

A highly loaded compressor cascade is analyzed by means of time-resolved 3D RANS simulations. Due to the low aspect ratio of the cascade, strong three-dimensional effects emerge, such as large corner vortices and trailing edge separation at the midspan. The feasibility of the simulation using a commercial software and the applicability of controlling the separated regions using zero net mass flux synthetic jets is analyzed. The work includes two control concepts that are investigated separately. One aims to affect the secondary flow emerging from the sidewalls via actuation at the cascade casing walls. The other aims to reattach the separated flow to the blade suction side using an actuator on the blade. Beneficial flow control parameters characterizing a synthetic jet are determined for both locations by a systematic variation. Special attention is drawn to the global efficiency of the stator cascade by means of total pressure loss and pressure rise.

Interaction of a synthetic jet with the flow over a low aspect ratio cylinder

2013 ◽  
Vol 25 (6) ◽  
pp. 064104 ◽  
Author(s):  
E. P. DeMauro ◽  
C. M. Leong ◽  
M. Amitay
Keyword(s):  
Aspect Ratio ◽  
Synthetic Jet ◽  
Low Aspect Ratio

Vortex formation of a finite-span synthetic jet: effect of rectangular orifice geometry

2014 ◽  
Vol 745 ◽  
pp. 180-207 ◽  
Author(s):  
Tyler Van Buren ◽  
Edward Whalen ◽  
Michael Amitay
Keyword(s):  
Aspect Ratio ◽  
Near Field ◽  
Vortex Formation ◽  
Synthetic Jet ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Structures ◽  
Geometrical Parameters ◽  
Neck Length ◽  
Finite Span ◽  
Aspect Ratios

AbstractThe formation and evolution of flow structures of a finite-span synthetic jet issuing into a quiescent flow were investigated experimentally using stereoscopic particle image velocimetry (SPIV). The effect of two geometrical parameters, the orifice aspect ratio and the neck length, were explored at a Strouhal number of 0.115 and a Reynolds number of 615. Normalized orifice neck lengths of 2, 4 and 6 and aspect ratios of 6, 12, and 18 were examined. It was found that the effect of the aspect ratio is much larger than the effect of the neck length, and as the aspect ratio increases the size of the edge vortices decreases and the presence of secondary structures is more evident. Moreover, axis switching was observed and its streamwise location increases as the aspect ratio increases. The effect of the neck length on the flow structures and the evolution of the synthetic jet was found to be secondary, where the effect was only in the very near field (i.e. close to the jet’s orifice).

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