Abstract
The flow separation behind a two-dimensional backward facing step is controlled by synthetic jet which is different from traditional ones. The synthetic jet is generated from a 2 mm horizontal slot which is at up corner of the step and facing downstream direction. In order to investigate the effectiveness of the synthetic jet at different actuation frequencies (0, 35, 50 and 100 Hz), 2C-2C particle image velocimetry and fluorescence oil-film was used to indicate the flow pattern on the surface and measure quantitatively the skin friction downstream of the step. The velocity vector field as well as global skin friction clearly indicates reduction of the reattachment length under proper actuation. The comparisons among frequencies indicate that the reattachment length depends on the actuation frequencies. The most effective reduction of reattachment length as much as 43.7% is achieved at the frequency of 100 Hz, corresponding to a Strouhal number Sth ≈ 0.3, based on the free-stream velocity and step height. The Reynolds shear stress is considerably increased and large-scale vortices are analyzed. The skin friction downstream is increased by 20% at the frequency of 35 Hz (Sth ≈ 0.026). In the conclusion, the streaming mechanism of a synthetic jet is briefly discussed.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Ming X, Dai CH (1991) A new phenomenon of acoustic streaming. Acta Mech Sinica 7(3). In: Proceedings of the international conference on fluid dynamics measurement and its applications, Beijing China, Oct 1989
Glezer A (1990) The formation of vortex rings. Phys Fluid 31(12)
Glezer A, Amitay M (2002) Synthetic jet. J Fluid Mech 34
Raffel M, Willert CE, Wereley ST, Kompenhans J (2007) Particle image velocimetry: a practical guide. Springer, Berlin
Squire LC (1961) The motion of a thin oil sheet under the boundary layer on a body. J Fluid Mech 11(2):161–179
Tanner LH, Blows LG (1976) A study of the motion of oil films on surfaces in air flow, with application to the measurement of skin friction. J Phys E Sci Instrum 9(3):194–202
Liu T, Sullivan JP (1998) Luminescent oil-film skin friction meter. AIAA J 36(8):1460–1465
Liu T, Woodiga S, Montefort J, Conn KJ, Shen L (2009) Global skin friction diagnostics in separated flows using luminescent oil. J Flow Vis Image Process 16(1):19–39
Winter KG (1977) An outline of the techniques available for measurement of skin friction in turbulent boundary layer. Progr Aerospace Sci 18:1–57
Ma X, Geisler R, Agocs J, Schröder A (2015) Investigation of coherent structures generated by acoustic tube in turbulent flow separation control. Exp Fluids 56:46
Hussain F, Reynolds WC (1970) The mechanics of an organized wave in turbulent shear layer. J Fluid Mech 41:241–258
Hussain F (1986) Coherent structures and turbulence. J Fluid Mech 173:303–356
Sirovich L (1987) Turbulence and the dynamics of coherent structures. Part 1: coherent structure. Q Appl Math 45(3):561–571
Meyer KE, Pedersen JM, Özcan O (2007) A turbulent jet in crossflow analysed with proper orthogonal decomposition. J Fluid Mech 583:199–227
Perrin R, Braza M, Cid E, Cazin S, Barthet A, Sevrain A, Mockett C, Thiele F (2007) Obtaining phase averaged turbulence properties in the near wake of a circular cylinder at high Reynolds number using POD. Exp Fluids 43:341–355
Bhattacharjee S, Scheelke B, Troutt TR (1986) Modification of vortex interactions in a reattaching separated flow. AIAA J 24(4):623–629
Fukagata K, Iwamoto K, Kasagi N (2002) Contribution of Reynolds stress distribution to the skin friction in wall-bounded flows. Phys Fluids 14(11):L73–L76
Acknowledgements
The authors would like to thank the EU-China co-funded “MARS” project for supporting the active flow control research. We are also grateful to the Nanjing University of Aeronautics and Astronautics and German Aerospace Center for great support the experiments.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 Springer Nature Switzerland AG
About this chapter
Cite this chapter
Ming, X., Ma, X., Geisler, R., Li, P. (2020). Effective Synthetic Jet Control for Separation Control on BFS. In: Qin, N., Periaux, J., Bugeda, G. (eds) Advances in Effective Flow Separation Control for Aircraft Drag Reduction. Computational Methods in Applied Sciences, vol 52. Springer, Cham. https://doi.org/10.1007/978-3-030-29688-9_14
Download citation
DOI: https://doi.org/10.1007/978-3-030-29688-9_14
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-29687-2
Online ISBN: 978-3-030-29688-9
eBook Packages: EngineeringEngineering (R0)