Topical Problems of Fluid Mechanics


Institute of Thermomechanics AS CR, v.v.i.	CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics	MIO Université du Sud Toulon Var - AMU - CNRS - IRD	Czech Pilot centre ERCOFTAC

Synthetic Jet Characteristic Velocity Estimated on the Basis of Momentum Flux Measurement
J. Kordík, Z. Trávníček
Abstract:
The paper compares two methods of evaluation of synthetic jet characteristic velocity. The first method of the characteristic velocity estimation is based on a simple measurement of the synthetic jet momentum flux (the jet thrust) by means of precision scales. The second method is a standard one, it is based on spatial-temporal integration of the velocity profile at the synthetic jet actuator nozzle exit. The velocity profile was obtained here using hot-wire measurements in air. Comparison of the methods is based on dimensionless stroke length of the synthetic jet. It is confirmed that the results of both methods are nearly the same for higher dimensionless stroke length. On the other hand, if the jet regime approaches to the synthetic jet criterion threshold (i.e. to the dimensionless stroke length of 0.5) the results of both methods diverge. Using the current results a correction is suggested for the momentum-flux-based method to match the standard one.
Keywords:
synthetic jet, synthetic jet actuator, momentum flux, jet thrust

Fulltext: PDF DOI: https://doi.org/10.14311/TPFM.2018.023

In Proceedings Topical Problems of Fluid Mechanics 2018, Prague, 2018 Edited by David Šimurda and Tomáš Bodnár, pp. 175-182 ISBN 978-80-87012-65-9 (Print) ISSN 2336-5781 (Print)