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Properties of a sweeping jet emitted from a fluidic oscillator

  • Florian Ostermann (a1), Rene Woszidlo (a1), C. Navid Nayeri (a1) and C. Oliver Paschereit (a1)


This experimental study investigates the flow field and properties of a sweeping jet emitted from a fluidic oscillator into a quiescent environment. The aspect ratio of the outlet throat is 1. Stereoscopic particle image velocimetry is employed to measure the velocity field plane-by-plane. Simultaneously acquired pressure measurements provide a reference for phase correlating the individual planes yielding three-dimensional, time-resolved velocity information. Lagrangian and Eulerian visualization techniques illustrate the phase-averaged flow field. Circular head vortices, similar to the starting vortex of a steady jet, are formed repetitively when the jet is at its maximum deflection. The quantitative jet properties are determined from instantaneous velocity data using a cylindrical coordinate system that takes into account the changing deflection angle of the jet. The jet properties vary throughout the oscillation cycle. The maximum jet velocity decays much faster than that of a comparable steady jet indicating a higher momentum transfer to the environment. The entrainment rate of the spatially oscillating jet is larger than for a steady jet by a factor of 4. Most of the mass flow is entrained from the direction normal to the oscillation plane, which is accompanied by a significant increase in jet depth compared to a steady jet. The high entrainment rate results from the enlarged contact area between jet and ambient fluid due to the spatial oscillation. The jet’s total force exceeds that of an idealized steady jet by up to 30 %. The results are independent of the investigated oscillation frequencies in the range from 5 to 20 Hz.


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Bobusch, B. C., Woszidlo, R., Bergada, J. M., Nayeri, C. N. N. & Paschereit, C. O. 2013 Experimental study of the internal flow structures inside a fluidic oscillator. Exp. Fluids 54 (6), 1559.
Bremhorst, K. 1979 Unsteady subsonic turbulent jets. In Recent Developments in Theoretical and Experimental Fluid Mechanics, pp. 480500. Springer.
Bremhorst, K. & Hollis, P. G. 1990 Velocity field of an axisymmetric pulsed, subsonic air jet. AIAA J. 28 (12), 20432049.
Choutapalli, I., Krothapalli, A. & Arakeri, J. H. 2009 An experimental study of an axisymmetric turbulent pulsed air jet. J. Fluid Mech. 631, 2363.
Faris, G. N.1963 Some entrainment properties of a turbulent axi-symmetric jet. Tech. Rep. Mississippi State University Department of Aerophysics.
Garcia, D. 2010 A fast all-in-one method for automated post-processing of PIV data. Exp. Fluids 50 (5), 12471259.
Gregory, J. & Tomac, M. N. 2013 A review of fluidic oscillator development. In 43rd AIAA Fluid Dynamics Conference. AIAA.
Grinstein, F. F., Gutmark, E. & Parr, T. 1995 Near field dynamics of subsonic free square jets. A computational and experimental study. Phys. Fluids 7 (6), 14831497.
Haller, G. 2001 Lagrangian structures and the rate of strain in a partition of two-dimensional turbulence. Phys. Fluids 13 (11), 33653385.
Jeong, J. & Hussain, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 6994.
Krothapalli, A., Baganoff, D. & Karamcheti, K. 1981 On the mixing of a rectangular jet. J. Fluid Mech. 107, 201220.
Lacarelle, A. & Paschereit, C. O. 2012 Increasing the passive scalar mixing quality of jets in crossflow with fluidics actuators. J. Engng Gas Turbines Power 134 (2), 021503.
Mi, J., Nathan, G. J. & Luxton, R. E. 2001 Mixing characteristics of a flapping jet from a self-exciting nozzle. Flow Turbul. Combust. 67 (1), 123.
Ostermann, F., Woszidlo, R., Nayeri, C. & Paschereit, C. O. 2015a Experimental comparison between the flow field of two common fluidic oscillator designs. In 53rd AIAA Aerospace Sciences Meeting. AIAA.
Ostermann, F., Woszidlo, R., Nayeri, C. N. & Paschereit, C. O. 2015b Phase-averaging methods for the natural flowfield of a fluidic oscillator. AIAA J. 53 (8), 23592368.
Ostermann, F., Woszidlo, R., Nayeri, C. N. & Paschereit, C. O.2018 Experimental three-dimensional velocity data of a sweeping jet from a fluidic oscillator. Technische Universität Berlin.
Platzer, M. F., Simmons, J. M. & Bremhorst, K. 1978 Entrainment characteristics of unsteady subsonic jets. AIAA J. 16 (3), 282284.
Quinn, W. R. 1992 Streamwise evolution of a square jet cross section. AIAA J. 30 (12), 28522857.
Quinn, W. R. & Militzer, J. 1988 Experimental and numerical study of a turbulent free square jet. Phys. Fluids 31 (5), 10171025.
Raman, G., Hailye, M. & Rice, E. J. 1993 Flip-flop jet nozzle extended to supersonic flows. AIAA J. 31 (6), 10281035.
Ricou, F. P. & Spalding, D. B. 1961 Measurements of entrainment by axisymmetrical turbulent jets. J. Fluid Mech. 11 (1), 2132.
Schlichting, H. & Gersten, K. 2006 Grenzschicht-Theorie (German Edition), 10th edn. Springer.
Schmidt, H.-J., Woszidlo, R., Nayeri, C. N. & Paschereit, C. O. 2015 Drag reduction on a rectangular bluff body with base flaps and fluidic oscillators. Exp. Fluids 56 (7).
Schmidt, H. J., Woszidlo, R., Nayeri, C. N. & Paschereit, C. O. 2017 Separation control with fluidic oscillators in water. Exp. Fluids 58 (8), 106.
Seele, R., Tewes, P., Woszidlo, R., McVeigh, M. A., Lucas, N. J. & Wygnanski, I. J. 2009 Discrete sweeping jets as tools for improving the performance of the V-22. AIAA J. Aircraft 46 (6), 20982106.
Seifert, A., Stalnov, O., Sperber, D., Arwatz, G., Palei, V., David, S., Dayan, I. & Fono, I. 2009 Large trucks drag reduction using active flow control. In The Aerodynamics of Heavy Vehicles II: Trucks, Buses, and Trains, pp. 115133. Springer.
Sforza, P. M., Steiger, M. H. & Trentacoste, N. 1966 Studies on three-dimensional viscous jets. AIAA J. 4 (5), 800806.
Sieber, M., Ostermann, F., Woszidlo, R., Oberleithner, K. & Paschereit, C. O. 2016 Lagrangian coherent structures in the flow field of a fluidic oscillator. Phys. Rev. Fluids 1 (5), 050509.
Simmons, J. M., Platzer, M. F. & Smith, T. C. 1978 Velocity measurements in an oscillating plane jet issuing into a moving air stream. J. Fluid Mech. 84 (1), 3353.
Srinivas, T., Vasudevan, B. & Prabhu, A. 1988 Performance of fluidically controlled oscillating jet. In Turbulence Management and Relaminarisation (ed. Liepmann, H. W. & Narasimha, R.), pp. 485494. Springer.
Viets, H. 1975 Flip-flop jet nozzle. AIAA J. 13 (10), 13751379.
Von Gosen, F., Ostermann, F., Woszidlo, R., Nayeri, C. N. & Paschereit, C. O. 2015 Experimental investigation of compressibility effects in a fluidic oscillator. In 53rd AIAA Aerospace Sciences Meeting. AIAA.
Whalen, E. A., Lacy, D. S., Lin, J. C., Andino, M. Y., Washburn, A. E., Graff, E. C. & Wygnanski, I. J. 2015 Performance enhancement of a full-scale vertical tail model equipped with active flow control. In 53rd AIAA Aerospace Sciences Meeting. AIAA.
Woszidlo, R., Ostermann, F., Nayeri, C. N. & Paschereit, C. O. 2015 The time-resolved natural flow field of a fluidic oscillator. Exp. Fluids 56 (6).
Wygnanski, I. J. & Fiedler, H. 1969 Some measurements in the self-preserving jet. J. Fluid Mech. 38 (3), 577612.
Zaman, K. B. M. Q. 1996 Axis switching and spreading of an asymmetric jet: the role of coherent structure dynamics. J. Fluid Mech. 316, 127.
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Ostermann et al. supplementary movie
The three-dimensional flow field of a sweeping jet emitted from a fluidic oscillator visualized by the backward finite time Lyapunov exponent. Note that the top half of the boundary wall is omitted to provide unobstructed view.

 Video (1.4 MB)
1.4 MB


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