High frequency characterization of a sweeping jet actuator

Ott, Célestin; Gallas, Quentin; Delva, Jérôme; Lippert, Marc; Keirsbulck, Laurent

doi:10.1016/j.sna.2019.03.034

Cited by 11 publications

(2 citation statements)

References 25 publications

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“…The results showed the effect of compressibility on the oscillation frequency and deviation from the linear trend line. In another study, the high-frequency characterization of an SWJ actuator was performed experimentally above 500 Hz [45]. The acoustic field of SWJ actuators also measured at full-and half-scale [46].…”

Section: Introductionmentioning

confidence: 99%

Jet Oscillation Frequency Characterization of a Sweeping Jet Actuator

Kara

2020

Fluids

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The time-resolved flow field of a spatially oscillating jet emitted by a sweeping jet (SWJ) actuator is investigated numerically using three-dimensional Reynolds-averaged Navier–Stokes (3D-URANS) equations. Numerical simulations are performed for a range of mass flow rates providing flow conditions varying from incompressible to subsonic compressible flows. After a detailed mesh study, the computational domain is represented using two million hexagonal control volumes. The jet oscillation frequency is predicted by analyzing velocity time histories at the actuator exit, and a linear relationship between the jet oscillation frequency and time-averaged exit nozzle Mach number is found ( f = 511.22 M + 46.618 , R² = 0.97). The results of our numerical model are compared with data from the literature, and a good agreement is found. In addition, we confirmed that the Strouhal number is almost constant with the Mach number for the subsonic oscillating jet and has an average value of St = 0.0131. The 3D-URANS model that we presented here provides a computationally inexpensive yet accurate alternative to the researchers to investigate jet oscillation characteristics.

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Section: Introductionmentioning

confidence: 99%

Jet Oscillation Frequency Characterization of a Sweeping Jet Actuator

Kara

2020

Fluids

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“…It was combined with a high-speed camera to visualize and investigate the internal dynamics of the SWJA using the Fourier transformation, phase information, and the Hilbert transformation [13]. Ott et al tried to find the time-space interface of SWJAs for high sweeping frequencies [14]. Another approach to the design optimization of the SWJA to increase the peak jet velocity output and pressure drop reduction was carried out by Jeong [15].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Exit Nozzle Geometry on Sweeping Jet Actuator Performance

Alam

Kara

2022

Fluids

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When pressurized with a fluid, the sweeping jet actuator (SWJA) emits a self-induced and self-sustained temporally continuous, but spatially oscillating bi-stable jet at the outlet. The SWJA adds up local momentum using the Coanda extension without any moving parts and, therefore, can be a promising tool for suppressing aerodynamic flow separation. However, the SWJA needs to be integrated into curved aerodynamic surfaces with an angle. The present study focuses on investigating the effects of various exit nozzle geometries on the flow field. The geometric parameters considered were the exit nozzle angle, diffuser arm length, and curvature. The working fluid was air, and the mass flow rate was 0.015 lb/s. A set of time-dependent flow fields was computed using a two-dimensional unsteady Reynolds-averaged Navier–Stokes (URANS) simulation. The time history of pressure was recorded inside the upper and lower feedback channels. The jet oscillation frequency was obtained by employing the fast Fourier transform (FFT) for all datasets. The results were compared against the baseline case and data available in the literature. The results showed that external geometric variations at the nozzle exit had a negligible impact on the oscillation frequency. However, there were notable effects on the pressure and velocity distribution in the flow field, indicating that the actuator had sensitivity towards the geometric variation of the exit nozzle—the wider the exit nozzle, the lower the downstream velocity. Notably, we observed that the mean velocity at the exit nozzle downstream for the curvature case was 40.3% higher than the reference SWJA.

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Pulsed jet phase-averaged flow field estimation based on neural network approach

et al. 2021

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Single hot-wire velocity measurements have been conducted along a three-dimensional measurement grid to capture the flow-field induced by a 45°inclined slotted pulsed jet. Based on the periodic behavior of the flow, two different estimation methods have been implemented. The first one, considered as the reference base-line, is the conditional approach which consists in the redistribution of the experimental data into spaceand time-resolved three-dimensional velocity fields. The second one uses a neural network to estimate 3D velocity fields given spatial coordinates and time. This paper compares the two methods for a complete flow-field estimation based on hot-wire measurements. Results suggest that the neural network is tailored to capture the phase-averaged dynamic response of the jet induced by the actuator, and identify the coherent structures in the flow field. Interesting performances are also observed when degrading the learning database, meaning that neural networks can be used to drastically improve the temporal or spatial resolution of a flow field estimation compared to the experimental data resolution.

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High frequency characterization of a sweeping jet actuator

Cited by 11 publications

References 25 publications

Jet Oscillation Frequency Characterization of a Sweeping Jet Actuator

Jet Oscillation Frequency Characterization of a Sweeping Jet Actuator

The Influence of Exit Nozzle Geometry on Sweeping Jet Actuator Performance

Pulsed jet phase-averaged flow field estimation based on neural network approach

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