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Novel Nozzle Shapes for Synthetic Jet Actuators Intended to Enhance Jet Momentum Flux

Institute of Thermomechanics of the Czech Academy of Sciences, Dolejškova 5, 182 00 Prague, Czech Republic
Author to whom correspondence should be addressed.
Actuators 2018, 7(3), 53;
Received: 27 July 2018 / Revised: 14 August 2018 / Accepted: 25 August 2018 / Published: 28 August 2018
(This article belongs to the Special Issue Synthetic Jet Actuators)
PDF [2380 KB, uploaded 28 August 2018]


An axisymmetric synthetic jet actuator based on a loudspeaker and five types of flanged nozzles were experimentally tested and compared. The first (reference) type of nozzle was a common sharp-edged circular hole. The second type had a rounded lip on the inside. The third nozzle type was assembled from these two types of nozzles—it had a rounded lip on the inside and straight section on the outside. The fourth nozzle was assembled using orifice plates such that the rounded lips were at both inner and outer nozzle ends. The last nozzle was equipped with an auxiliary nozzle plate placed at a small distance downstream of the main nozzle. The actuators with particular nozzles were tested by direct measurement of the synthetic jet (SJ) time-mean thrust using precision scales. Velocity profiles at the actuator nozzle exit were measured by a hot-wire anemometer. Experiments were performed at eight power levels and at the actuator resonance frequency. The highest momentum flux was achieved by the nozzle equipped with an auxiliary nozzle plate. Namely, an enhancement was approximately 31% in comparison with an effect of the reference nozzle at the same input power. Furthermore, based on the cavity pressure and the experimental velocity profiles, parameters for a lumped element model (mass of moving fluid and pressure loss coefficient) were evaluated. These values were studied as functions of the dimensionless stroke length. View Full-Text
Keywords: synthetic jet; synthetic jet actuator; momentum flux; jet thrust; nozzle shape synthetic jet; synthetic jet actuator; momentum flux; jet thrust; nozzle shape

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Kordík, J.; Trávníček, Z. Novel Nozzle Shapes for Synthetic Jet Actuators Intended to Enhance Jet Momentum Flux. Actuators 2018, 7, 53.

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