Numerical Study of Internal Flow Structures in a Sweeping Jet Actuator

Abstract

This study focuses on the generation and interaction of internal flow structures, jet oscillation process, and pressure drop mechanism of a Sweeping Jet Actuator. Timedependent numerical analysis was performed over a range of inlet mass flow rates. The effect of varying inlet mass flow rate on the sweeping jet oscillation frequency was calculated and a strong agreement was found with the experimental measurements. The velocity, temperature and pressure fields are provided. The complex flow field inside the Sweeping Jet Actuator for half an oscillation cycle are presented by velocity magnitude and total pressure contours. Formation of vortices from sharp corners in the actuator core surfaces were observed, and their role in jet oscillation is shown.

Analysis of the Forces Driving the Oscillations in 3D Fluidic Oscillators

“…From their applications in flow control, it is interesting to mention their use in combustion control [3], flow deflection and mixing enhancement [4], flow separation modification in airfoils [5], boundary layer modification on hump diffusers used in turbomachinery [6], flow separation control on compressors stator vanes [7], gas turbine cooling [8], drag reduction on lorries [9], and noise reduction in cavities [10].Despite the existence of particular fluidic oscillator configurations, like the one introduced by Uzol and Camci [11], which was based on two elliptical cross-sections placed transversally and an afterbody located in front of them, or the one proposed by Huang and Chang [12], which was a V-shaped fluidic oscillator, most of the recent studies on oscillators focused on two main, very similar, canonical geometries, which Ostermann et al [13] called the angled and the curved oscillator geometries. Some very recent studies on the angled geometry are [13][14][15][16][17][18][19][20][21][22][23], while the curved geometry was studied by [4,10,13,[23][24][25][26][27][28][29][30][31][32][33]. Ostermann et al [13], compared both geometries, concluding that the curved one was energetically the most efficient.One of the first analyses of the internal flow on an angled fluidic oscillator was undertaken by Bobusch et al [17].…”

High frequency characterization of a sweeping jet actuator

“…• Woszidlo R. [20] • Raman G. [19] • Ott C. The literature gives numerous characterization methods such as local time-resolved at high sweeping frequency ( [8], [19], [20], [21]), spatially-resolved snapshots ( [22]), spacetime resolved at low sweeping frequency ( [23], [22], [24]), numerical analysis and simulations ( [25], [26], [27], [28]). Since the flow control actuation by sweeping jet is relatively recent [29], the state of art shows a lack of characterization process in order to correctly define the high frequency dynamic response.…”

Aircraft Control Surfaces Using Co-flow Jet Active Flow Control Airfoil

“…Active Flow control (AFC) as a method to enhance lift has a great potential to reduce the size and weight of control surfaces [1][2][3][4][5][6][7]. AFC has been used to control the separated flow of vertical tails to enhance aerodynamic performance and mitigate flutter [8][9][10][11][12][13][14][15][16][17]. The research of Boeing and NASA in [8][9][10][11][12][13][14][15] on vertical tails using sweeping jets and synthetic jets AFC represents the state of the art.…”

“…A side force increase of 13% to 16% was estimated at 30° rudder deflection for critical sideslip range between β = 0° and -7.5° with the activation of AFC. Kara [16,17] analyzed the complex flow inside the sweeping jet for design optimization of actuator geometry with minimum pressure loss. However, those studies [8][9][10][11][12][13][14][15][16][17] have not report sufficient results on energy expenditure of the sweeping jets actuators, which tend to suffer large energy loss due to jet sweeping, turning, and flow separation.…”

“…Kara [16,17] analyzed the complex flow inside the sweeping jet for design optimization of actuator geometry with minimum pressure loss. However, those studies [8][9][10][11][12][13][14][15][16][17] have not report sufficient results on energy expenditure of the sweeping jets actuators, which tend to suffer large energy loss due to jet sweeping, turning, and flow separation. This paper explores a new control surfaces active flow control using Co-Flow Jet (CFJ) airfoil, which is a zero-net mass flux (ZNMF) flow control that has demonstrated radical lift enhancement, drag reduction, and ultra-high stall AoA [2,5,18,19,20,21,22,23,24,25,26,27].…”