The Flow Over a Backward Facing Step Subjected to Multiple Synthetic Jet Actuators

Sassoon, Aaron M.; Hubbard, James E.; Flatau, Alison B.; Hasnain, Zohaib

doi:10.2514/6.2013-3166

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…There were some consensuses regarding the parametric analyses of jet parameters, such as the influences from jet momentum coefficient, location of jet and excitation frequency. In the investigations of the implications of synthetic jet location, a general good agreement was concluded that the jet adjacent to the separation position enabled the jet vortex penetrate into large separated flow state more efficiency 27 , and thus it reduced the substantial size of the separation vortex and delay the stall of an airfoil 28,29 . Further, as another influential parameter, the momentum coefficient of the synthetic jet was demonstrated to be proportional to the growth of aerodynamic characteristics of an airfoil in the previous studies [30][31][32] , and the control effects tended to be stabilized with momentum coefficient exceeding a critical value 33 .…”

Section: Openmentioning

confidence: 95%

Wind-tunnel tests of synthetic jet control effects on airfoil flow separation

Zhao

Chen

2022

Sci Rep

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To find out the comprehensive principles of synthetic jet control effects on airfoil stall characteristics, fundamental contrastive wind-tunnel tests were conducted systematically. By using six-component balance, Particle Image Velocimetry (PIV) technology and boundary layer probe, the measurements of model aerodynamic forces, the whole velocity field over airfoil and velocity profiles in the boundary layer were conducted, respectively. Based upon the experimentally parametric analyses of synthetic jet control on airfoil, it is concluded that the incline angle of synthetic jet has an important impact on both the flow in boundary layer and aerodynamic forces of airfoil. A tangential jet inject energy and accelerate the velocity of flow in inner boundary layer thus has a better control effects on delay stall of airfoil when the momentum coefficient of jet is relatively large, and the normal jet helps to enlarge the thickness of boundary layer which is proved to have better control effects on flow separation control and improving the aerodynamic characteristics of airfoil when the momentum coefficient of a jet is relatively small.

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Section: Openmentioning

confidence: 95%

Wind-tunnel tests of synthetic jet control effects on airfoil flow separation

Zhao

Chen

2022

Sci Rep

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“…Virtual shaping using SJAs has been studied in great detail. Some of the more modern applications include work done by Sassoon et al 18 who demonstrated the ability of SJAs to alter the pressure distribution over a backward facing step in a cross-flow. More recently, Feng and Wang 19 demonstrated the ability of SJAs to alter the flow over a cylinder, thereby changing its lift and drag properties.…”

Section: Motivation: Sja Background and Applicationsmentioning

confidence: 98%

Dynamic Flow Control over Aerodynamic Bodies using Phased Array Vectored Synthetic Jet Actuation

Hasnain

Trollinger

Hubbard

et al. 2015

33rd AIAA Applied Aerodynamics Conference

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An experimental investigation into the flow control capabilities of synthetic jet actuators (SJAs) was performed. An array consisting of two synthetic jet actuators was designed and fabricated. The effects of vectoring an array on streamline location and pressure distribution were studied using Particle Image Velocimetry (PIV) and static pressure measurements. Three different bodies were tested: a flat plate, a two-dimensional cylinder representative of a bluff body, and a modified two-dimensional NACA 0018 airfoil representative of a streamlined body. Actuation was performed at Array Momentum Coefficient (Cµ) values ranging from 0.8% to 8%. The relative phase of operation, ϕ, of the individual actuators in the array was varied to control the direction of the jet trajectory. PIV was used to study the streamline deflection pattern over a flat plate. A significant change in streamline deflection pattern was observed in response to changing the phase. For the case of the cylinder, actuator arrays were placed at +/-70° locations with respect to the free stream direction. Actuation was performed at a momentum coefficient value of approximately 0.8% and the phase was varied. Pressure measurements were made over the surface of the cylinder. A 10% decrease in pressure drag was observed for specific cases of phasing. Pressure measurements indicated that the point of separation, in response to actuation at this specific phase angle, was delayed by approximately 20°. An array of actuators was also embedded in a modified NACA 0018 airfoil subjected to a low speed cross-flow. The pressure coefficient (CP) was calculated over the surface. For this case, vectored actuation resulted in a reduction in pressure drag and a simultaneous increase in lift. The benefits of phased actuation over different types of aerodynamic bodies are demonstrated and analyzed using different experimental methods. Nomenclature φ = Operating phase difference between array actuators 1 and 2 b = Streamwise dimension of orifice (width) c = Characteristic Length Scale (used for calculating Cμ and F*) Cμ = Actuator/Array Momentum Coefficient (2bUJ 2 / cU 2 ) CD = Drag coefficient CL = Section Lift coefficient

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The Flow Over a Backward Facing Step Subjected to Multiple Synthetic Jet Actuators

Cited by 2 publications

References 14 publications

Wind-tunnel tests of synthetic jet control effects on airfoil flow separation

Wind-tunnel tests of synthetic jet control effects on airfoil flow separation

Dynamic Flow Control over Aerodynamic Bodies using Phased Array Vectored Synthetic Jet Actuation

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