Experimental study of stall control over an airfoil with dual excitation of separated shear layers

Ebrahimi, Abbas; Hajipour, Majid; Ghamkhar, Kamran

doi:10.1016/j.ast.2018.09.027

Cited by 20 publications

(8 citation statements)

References 28 publications

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“…Nati et al [15] performed an experimental investigation on controlling of vortex shedding from a blunt trailing edge by fixing plasma actuators in the region of the trailing edge, and demonstrated that plasma actuators can greatly reduce the total kinetic energy due to suppressing vortex shedding from the trailing edge. Recently, Abbas et al [16] investigated experimentally control of over an airfoil stall by using dual excitations and found that, compared with the approach of using a single plasma actuator at the trailing edge solely, the simultaneous excitation at both the trailing edge and on the suction side was more effective for a full stall control.…”

mentioning

confidence: 99%

Control of cylinder wake flow and noise through a downstream porous treatment

Mao

2019

Aerospace Science and Technology

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Various passive and active methods have been developed to control flow separation from bluff bodies. However, these methods require adjusting features of the solid surface, such as modifying its geometry or porosity, or applying external force or momentum. This paper develops an off-body-based method, without adjusting any features of the solid surface, for controlling the unsteady flow separation by fixing porous materials downstream of bluff bodies. Numerical study on flow past a circular cylinder at a subcritical Reynolds number is performed, and the result indicates that the added downstream porous material changes flow in the wake and re-laminarizes the turbulent flow around the curved cylinder surface, reducing the wall pressure fluctuation around the cylinder. therefore, the associated aerodynamic noise is reduced greatly.

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mentioning

confidence: 99%

Control of cylinder wake flow and noise through a downstream porous treatment

Mao

2019

Aerospace Science and Technology

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Section: Classification and Description Of Flow Control Methodsmentioning

confidence: 58%

“…According to the results, actuation manipulates the shear-layer instabilities and modify the wake patterns remarkably. Although the front DBD actuator contributes more to the increases in lift and lift-to-drag ratio, the proposed dual excitation seems most promising for full-stall control in a wide range of excitation frequencies, as reported by Ebrahimi et al 130 Zhang et al 131 study flow control on a circular cylinder by two symmetric DBD actuators located at the top and bottom surface. Each actuator induces a pair of counter-rotating vortices traveling upstream and downstream.…”

Section: Active Flow Controlmentioning

confidence: 83%

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Current state and future trends in boundary layer control on lifting surfaces

Svorcan

Wang

Griffin

2022

Advances in Mechanical Engineering

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Successful flow control may bring numerous benefits, such as flow stabilization, flow reattachment, separation delay, drag reduction, lift increase, aerodynamic performance improvement, energy efficiency increase, shock delay or weakening, noise reduction, etc. For these purposes, many different flow control devices, which can be classified as passive, semi-active and active, have been designed and tested. This review paper aims to highlight the most promising and commonly employed boundary layer control methods as well as outline their potential in specific applications in aerospace and energy engineering. Referenced studies, performed on various geometries (flat plates, channels, airfoils, wings, blades, cylinders), are primarily numerical or experimental. Although enhanced aerodynamic performance is achieved in many cases, further research is required to draw general conclusions. This paper aims to demonstrate that, in the future, we may expect further developments of flow control actuators, as well as their increased application.

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“…They also studied the impact of unsteady actuation frequency on separation delay of this configuration. Ebrahimi et al 29 experimentally measured the pressure distribution over an NACA 0015 airfoil employing the actuator configuration they had already used in their previous research. 26 The actuators were activated at both single and combinational modes, and the results showed that the latter case was more efficient for the stall recovery.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of a horizontal axis wind turbine airfoil performance using single dielectric barrier discharge plasma actuator

Fadaei

Davari

Sabetghadam

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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Wind turbines are of the most promising devices to cut down carbon emissions. However, some phenomena that adversely affect their performance are inevitable. The aim of the present paper is to investigate flow separation prevention exploiting leading edge (LE) single dielectric barrier discharge plasma actuator (SDBD-PA) on an airfoil belonging to a section of a locally developed wind turbine. The numerical results of the surface pressure distribution over the airfoil were compared with the experimental measurements carried out by the authors on the same blade section, and good agreement was found between numerical and experimental data for both plasma-OFF and plasma-ON cases. An in-depth parametric numerical investigation was then carried out to provide a better understanding of the flow behavior affected by the activation of PA over the same airfoil at post stall angle of attacks (AOAs). According to the results, the frequency and voltage of actuation, AOA, and free stream velocity are shown to have strong impacts on separation delay and actuation effectiveness. In Reynolds number of 2.85 × 105, the maximum PA effectiveness takes place at 21° which is approximately 312%, 307%, and 256% corresponding to the PA location of LE, 0.02 chord, and 0.15 chord, respectively. Also, maximum velocity of the domain is increased three times of the free stream velocity on average for three investigated Reynolds numbers at the frequency and voltage of 12 kHz and 12 kV, respectively. Furthermore, the size of the wake area noticeably contracts due to the presence of the SDBD-PA. The results clearly indicate that the lift and drag coefficients as well as the lift-to-drag ratio fit a linear variation pattern with the frequency of actuation. The variation rate of the aforementioned parameters becomes steeper as the peak voltage of actuation increases. Highly nonlinear aerodynamic responses and significant interactions were demonstrated between the investigated parameters.

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Experimental study of stall control over an airfoil with dual excitation of separated shear layers

Cited by 20 publications

References 28 publications

Control of cylinder wake flow and noise through a downstream porous treatment

Control of cylinder wake flow and noise through a downstream porous treatment

Current state and future trends in boundary layer control on lifting surfaces

Enhancement of a horizontal axis wind turbine airfoil performance using single dielectric barrier discharge plasma actuator

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