scispace - formally typeset
Search or ask a question
Topic

Starting vortex

About: Starting vortex is a research topic. Over the lifetime, 4785 publications have been published within this topic receiving 100419 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the authors used particle image velocimetry to understand the vortex-formation mechanisms of dielectric-barrier-discharge actuators in the laminar boundary layer.
Abstract: The streamwise vortices generated by dielectric-barrier-discharge plasma actuators in the laminar boundary layer were investigated using particle image velocimetry to understand the vortex-formation mechanisms. The plasma vortex generator was oriented along the primary flow direction to produce a body force in the spanwise direction. This created a spanwise-directed wall jet which interacted with the oncoming boundary layer to form a coherent streamwise vortex. It was found that the streamwise vortices were formed by the twisting and folding of the spanwise vorticity in the oncoming boundary layer into the outer shear layer of the spanwise wall jet, which added its own vorticity to increase the circulation along the actuator length. This is similar to the delta-shaped, vane-type vortex generator, except that the circulation was enhanced by the addition of the vorticity in the plasma jet. It was also observed that the plasma vortex was formed close to the wall with an enhanced wall-ward entrainment, which created strong downwash above the actuator.

87 citations

Journal ArticleDOI
TL;DR: In this paper, the tip vortex of a laminar flow wing was studied at a sectional lift-to-drag ratio of 60.8×104, where Γ is the total circulation and ν is the kinematic viscosity.
Abstract: The tip vortex of a laminar flow wing was studied at a sectional lift‐to‐drag ratio of 60. The vortex Reynolds number was Γ0/ν=7.8×104, where Γ0 is the total circulation and ν is the kinematic viscosity. At and near the wing the vortex core was turbulent with an axial jet. Downstream of the wing the jet rapidly dissipated and a wake developed in the core and intensity of turbulent velocities decreased. From 13 to 40 chord length periodic oscillations dominated the velocity fluctuations with little background turbulence. These instabilities had a symmetric and a helical mode with wavelength of the same order as the core diameter. In this range of distances along the vortex core the maximum axial, swirl, and fluctuating velocities vary slowly. At 40 chord lengths behind the wing there is a rapid change in these velocities. This change of state of the vortex core is accompanied by change of velocity fluctuations from periodic to turbulent. The core showed spatial excursions. Measurements up to 80 chord lengths downstream showed no self‐similar decay.

87 citations

Journal ArticleDOI
TL;DR: In this article, a numerical study of separation control has been made to investigate aerodynamic characteristics of NACA23012 airfoil with synthetic jets, and it was observed that the actual flow control mechanism and flow structure is fundamentally different depending on the range of synthetic jet frequency.

87 citations

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional Navier-Stokes solver was used to simulate a NACA0012 airfoil, oscillated sinusoidally in plunge, with a Reynolds number of 20,000.
Abstract: The flow over a NACA0012 airfoil, oscillated sinusoidally in plunge, is simulated numerically using a two-dimensional Navier-Stokes solver at a Reynolds number of 20,000. The wake of the airfoil is visualized using a numerical particle tracing method for high reduced frequencies (1.0

87 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the use of dielectric-barrier-discharge plasma actuators as vortex generators for flow separation control applications, and they found that the vortex generators were successful in reducing the separation region, even at plasma-to-free-stream velocity ratios of less than 10%.
Abstract: We investigated the use of dielectric-barrier-discharge plasma actuators as vortex generators for flow separation control applications. Plasma actuators were placed at a yaw angle to the oncoming flow, so that they produced a spanwise wall jet. Through interaction with the oncoming boundary layer, this created a streamwise longitudinal vortex. In this experimental investigation, the effect of yaw angle, actuator length and plasma-induced velocity ratio was studied. Particular attention was given to the vortex formation mechanism and its development downstream. The DBD plasma actuators were then applied in the form of co-rotating and counter-rotating vortex arrays to control flow separation over a trailing-edge ramp. It was found that the vortex generators were successful in reducing the separation region, even at plasma-to-free-stream velocity ratios of less than 10%.

86 citations


Network Information
Related Topics (5)
Reynolds number
68.4K papers, 1.6M citations
92% related
Boundary layer
64.9K papers, 1.4M citations
90% related
Vortex
72.3K papers, 1.3M citations
90% related
Turbulence
112.1K papers, 2.7M citations
89% related
Laminar flow
56K papers, 1.2M citations
87% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202336
202278
20217
20207
20196
201815