Abstract
In contrast to steady blowing jets, periodically generated vortex rings show great promise for increasing the efficiency of impingement cooling configurations. This study addresses the problem of crossflow superimposed on periodically generated vortex rings impinging on a flat plate. Frequency, duty cycle and equivalent stroke ratio of the vortex rings formed at constant jet-to-crossflow velocity ratio of 4.3 were varied. By means of time resolved PIV measurements, the parameter combinations were assessed with respect to the intensity of wall-bounded vorticity field induced by the vortices at the plate’s surface. Attenuation of the boundary layer renewal is observed if the vortex rings feature a trailing column during their formation. The frequency determines the spacing of subsequent vortices and the intensity of dynamic interaction. Vortex tilting occurs if the frequency is increased and the impact positions are affected. The duty cycle is used to relate the cooling power to the applied mass flux.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Gharib, M., Rambod, E., Shariff, K.: A universal time scale for vortex ring formation. J. Fluid Mech. 360, 121–140 (1998)
Janetzke, T., Nitsche, W., Täge, J.: Experimental investigations of flow field and heat transfer characteristics due to periodically pulsating impinging air jets. Heat Mass Transf. 45, 193–206 (2008)
Janetzke, T., Nitsche, W.: Time resolved investigations on flow field and quasi wall shear stress of an impingement configuration with pulsating jets by means of high speed PIV and surface hot wire array. Int. J. Heat Fluid Flow 30, 877–885 (2009)
Janetzke, T.: Experimentelle Untersuchungen zur Effizienssteigerung von Prallkühlkonfigurationen durch dynamische Ringwirbel hoher Amplitude. Dissertation, Technische Universität Berlin (2010)
Kataoka, K., Suguro, M., Degawa, H., Maruo, K., Mihata, I.: The effect of surface renewal due to largescale eddies on jet impingement heat transfer. Int. J. Heat Mass Transf. 30(3), 559–567 (1987)
Pagenkopf, U.: Untersuchung der lokalen konvektiven Transportvorgänge auf Prallflächen. PhD Thesis, Technische Hochschule Darmstadt (1996)
Raffel, M., Willert, C., Wereley, S., Kompenhans, J.: Particle Image Velocimetry—A Practical Guide, 2nd edn. Springer, Berlin (2007)
Sau, R., Mahesh, K.: Dynamics and mixing of vortex rings in crossflow. J. Fluid Mech. 604, 389–409 (2008)
Sau, R., Mahesh, K.: Optimization of pulsed jets in crossflow. J. Fluid Mech. 653, 365–390 (2010)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer International Publishing Switzerland
About this paper
Cite this paper
Kroll, H., Weiss, A., Nitsche, W. (2016). Experimental Investigation of Periodically Generated Vortex Rings in Crossflow Impinging on a Flat Plate. In: Dillmann, A., Heller, G., Krämer, E., Wagner, C., Breitsamter, C. (eds) New Results in Numerical and Experimental Fluid Mechanics X. Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 132. Springer, Cham. https://doi.org/10.1007/978-3-319-27279-5_56
Download citation
DOI: https://doi.org/10.1007/978-3-319-27279-5_56
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-27278-8
Online ISBN: 978-3-319-27279-5
eBook Packages: EngineeringEngineering (R0)