Numerical Study and Experimental Validation of the Interaction of Multiple Synthetic Jet Actuators with Cross Flow

Hasnain, Zohaib; Flatau, Alison B.; Hubbard, James E.; Mulinti, Rahul

doi:10.2514/6.2012-1247

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…This behaviour was also confirmed by Hasnain & Flatau (2012) who reproduced the interactions using simulations. After the phase angle exceeded 120 • , Smith & Glezer (2005) found the successive vortex pairs do not merge and the vortex pair that is lagging in phase begins to be influenced by the suction cycle at the adjacent orifice.…”

Section: Interactions Of Sj Arrayssupporting

confidence: 68%

Study of synthetic jets in boundary layers

Wen¹

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Section: Interactions Of Sj Arrayssupporting

confidence: 68%

Study of synthetic jets in boundary layers

Wen¹

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“…For specific operating conditions (phase difference, actuation frequency and mean blowing velocity) and orifice spacing, Orkwis and Filz (2003) found twin jets to have a net momentum contribution of 6% more than two individual SJAs. Furthermore, Hasnain et al (2012) observed the recirculation zone shape to change depending on the phase difference between the jets and the absence/presence of a crossflow. Hasnain et al (2012) also noted the vectoring behaviour in crossflow to be similar to quiescent flow conditions.…”

Section: B Twin Jets In Crossflowmentioning

confidence: 97%

“…Furthermore, Hasnain et al (2012) observed the recirculation zone shape to change depending on the phase difference between the jets and the absence/presence of a crossflow. Hasnain et al (2012) also noted the vectoring behaviour in crossflow to be similar to quiescent flow conditions. However, it was concluded that the dynamics of twin jets in crossflow cannot be simplified to a linear superposition of the dynamics of two individual single jets in crossflow.…”

Section: B Twin Jets In Crossflowmentioning

confidence: 97%

Interaction and vectoring of parallel rectangular twin jets in a turbulent boundary layer

Jankee

Ganapathisubramani

2021

Phys. Rev. Fluids

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The ability to impart momentum while maintaining a zero net mass flux renders synthetic jet actuators attractive tools for a wide variety of applications. Implementation of a single synthetic jet actuator for large-scale operations is unrealistic and as such, an array of actuators is usually desired during flow control processes. The added complexity of several synthetic jets in close proximity and the subsequent jet-jet interaction, in addition to interaction with the crossflow, represent an area of research yet to be fully explored. This paper encompasses a parametric study to investigate the interaction of a zero pressure gradient turbulent boundary layer (Reτ = 1300) with twin parallel synthetic jets, where the major axis of the rectangular orifices is aligned with the crossflow. Only the separation distance, s, and the phase difference, β, between the two orifices are varied. Geometrical parameters such as the orifice shape and aspect ratio (AR = 13), as well as fluidic properties such as the jet Strouhal number (St = 2.3) and the momentum coefficient (Cµ = 0.16) are kept constant throughout. Velocity fields acquired through stereoscopic PIV measurements at 5 downstream locations indicate noticeable differences in the flowfield and associated stresses. A limit in spacing is noted beyond which any subsequent increase results in the twin jets behaving as two independent synthetic jets. In comparison to a single synthetic jet in crossflow, the results demonstrate that twin jets operated at a specific phase difference and spacing can be equally, if not, more efficient for flow entrainment and momentum distribution.

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“…Smith and Glezer 17 observed a strong interaction for an actuator spacing at approximately 2.5 b (orifice widths). Additionally, a high aspect ratio was desired since such geometries lead to two-dimensional jets for heights of less than 20 orifice widths above the surface 6 . With this requirement under consideration, a pre-existing asymmetric actuator design, first developed by NASA 20 , was selected for modification.…”

Section: Actuator and Array Design And Characterizationmentioning

confidence: 99%

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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Numerical Study and Experimental Validation of the Interaction of Multiple Synthetic Jet Actuators with Cross Flow

Cited by 5 publications

References 6 publications

Study of synthetic jets in boundary layers

Study of synthetic jets in boundary layers

Interaction and vectoring of parallel rectangular twin jets in a turbulent boundary layer

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

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