Summary
The current work focusses on the spatio-temporal evolution of large scale coherent structures in the turbulent boundary layer of a plane channel both with and without microtile-based EMHD control. The heuristic concept behind the microtile designs that we have simulated apparently does not yield a successful drag reduction strategy (for the open-loop case [1]). In this work we investigate the flow response when the Lorentz force is applied with feedback conditioned on the advection of large-scale flow structures (e.g. hairpin vortices). We performed a long-time simulation conditioned on the passage of strong ejection events but obtained no reduction in skin friction. Based on short-time simulations we found that the near-wall flow structures undergo merely a spatial phase-shift when advecting above a single Lorentz force actuator: the structures are simply decelerated or accelerated with little change in their appearance, based on flow visualization. During this interaction of the applied Lorentz force with the flow, the Reynolds stress is unchanged.
Similar content being viewed by others
References
O'Sullivan, P. L., Biringen, S.: Direct simulations of low Reynolds number turbulent channel flow with EMHD Control. Phys. Fluids10, 1169–1181 (1998).
Nosenchuck, D. M., Brown, G. L.: Discrete spatial control of wall shear stress in a turbulent boundary layer. In: Near wall turbulent flows (So, R., Speziale, C. G., Launder, B. E., eds.), pp. 313–343. Elsevier 1993. Proceedings of an International Conference on Near-Wall Turbulent Flows held at Arizona State University, Tempe, AZ, March 15–17, 1993.
Henoch, C., Stace, J.: Experimental investigation of a salt water turbulent boundary layer modified by an applied streamwise magnetohydrodynamic body force. Phys. Fluids7, 1371–1383 (1995).
Bandyopadhyay, P. R., Castano, J. M.: Micro-tiles for electromagnetic turbulence control in saltwater-preliminary investigations. In: (Parkh, D. E., Agarwal, R. K., eds.): ASME Fluids Engineering Division 237. San Diego: ASME 1996.
Crawford, C. H., Karniadakis, G. E.: Reynolds stress analysis of emhd-conrolled wall turbulence. Part i. Streamwise forcing. Phys. Fluids9, 788–806 (1997).
Berger, T. W., Kim, J., Lee, C., Lim, J.: Turbulent boundary layer control utilizing the Lorentz force. Phys. Fluids12, 631–649 (2000).
Jung, W. J., Mangiavacchi, N., Akhavan, R.: Suppression of turbulence in wall-bounded flows by high-frequency spanwise oscillations. Phys. FluidsA4, 1605–1607 (1992).
Laadhari, F., Skandaji, L., Morel, R.: Turbulence reduction in a boundary layer by a local spanwise oscillating surface. Phys. Fluids6, 3218–3220 (1994).
Hatay, F. F., O'Sullivan, P. L., Biringen, S., Bandyopadhyay, P. R.: Numerical simulation of secondary flows in channels driven by applied Lorentz forces. AIAA J. Thermal Phys. Heat Transfer11, 446–453 (1997).
Alfredsson, P. H., Johansson, A. V.: On the detection of turbulence-generating events. J. Fluid Mech.139, 325–345 (1984).
Head, M. R., Bandyopadhyay, P.: New aspects of turbulent boundary-layer structure. J. Fluid Mech.107, 297–338 (1981).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
O'Sullivan, P.L., Biringen, S. Numerical experiments on feedback EMHD control of large scale coherent structures in channel turbulence. Acta Mechanica 152, 9–17 (2001). https://doi.org/10.1007/BF01176942
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01176942