TY - CHAP

T1 - On amplitude scaling of active separation control

AU - Stalnov, Oksana

AU - Seifert, Avraham

PY - 2010

Y1 - 2010

N2 - Various scaling options for the effects of excitation magnitude on the lift alternation due to zero-mass-flux periodic excitation for boundary layer separation control are examined. Physical scaling analysis leads to five amplitude parameters. The different scaling laws are examined using experimental data acquired at low Reynolds numbers and various angles of attack. The results indicate that both the velocity ratio and the momentum coefficient, commonly used for amplitude scaling of separation control applications, do not scale the current data-set. For 2D excitation with a Strouhal number of order unity, a Reynolds weighted momentum coefficient provides reasonable scaling. For 3D excitation with a Strouhal number greater than 10, the Reynolds scaled momentum coefficient, the Strouhal scaled velocity ratio and the newly defined vorticity-flux coefficient, all provide good scaling. The airfoil incidence variations are accounted for by using the velocity at the boundary layer edge at the actuation location, rather than the fixed free-stream velocity as a velocity scale. The main finding of this study is that the Reynolds number scaled momentum coefficient provides good amplitude scaling for the entire current data set.

AB - Various scaling options for the effects of excitation magnitude on the lift alternation due to zero-mass-flux periodic excitation for boundary layer separation control are examined. Physical scaling analysis leads to five amplitude parameters. The different scaling laws are examined using experimental data acquired at low Reynolds numbers and various angles of attack. The results indicate that both the velocity ratio and the momentum coefficient, commonly used for amplitude scaling of separation control applications, do not scale the current data-set. For 2D excitation with a Strouhal number of order unity, a Reynolds weighted momentum coefficient provides reasonable scaling. For 3D excitation with a Strouhal number greater than 10, the Reynolds scaled momentum coefficient, the Strouhal scaled velocity ratio and the newly defined vorticity-flux coefficient, all provide good scaling. The airfoil incidence variations are accounted for by using the velocity at the boundary layer edge at the actuation location, rather than the fixed free-stream velocity as a velocity scale. The main finding of this study is that the Reynolds number scaled momentum coefficient provides good amplitude scaling for the entire current data set.

UR - http://www.scopus.com/inward/record.url?scp=77950670004&partnerID=8YFLogxK

U2 - 10.1007/978-3-642-11735-0_5

DO - 10.1007/978-3-642-11735-0_5

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AN - SCOPUS:77950670004

SN - 9783642117343

T3 - Notes on Numerical Fluid Mechanics and Multidisciplinary Design

SP - 63

EP - 80

BT - Active Flow Control II

A2 - King, Rudibert

PB - Springer Berlin Heidelberg

ER -