Abstract
The suppression of post-stall separation over an unconventional 2-D airfoil at moderate Reynolds numbers (up to 106) using transverse synthetic (zero net mass flux) jet actuators is discussed. As shown by the authors in earlier investigations, the apparent modification of the surface shape by the interaction domain between the actuator jets and the cross flow results in a local displacement of the cross flow streamlines. The concomitant modification of the streamwise pressure gradient upstream of where the flow nominally separates in the baseline configuration can lead to complete suppression of separation over a significant range of angles of attack in the post-stall domain. While in the absence of flow control the airfoil is stalled at angles of attack exceeding 5°, actuation leads to either completely or partially attached flow within the entire range of angles tested (up to 25°) that is accompanied by a dramatic increase in lift and a corresponding decrease in pressure drag. Actuation is typically effected at frequencies that are an order of magnitude higher than the characteristic (shedding) frequency of the airfoil [i.e., St ~ O(10) rather than St ~ O(1)]. When the actuation frequency St is O(1), the reattachment is characterized by a Coanda-like tilting of the separated shear layer and the formation of large vortical structures at the driving frequency that persist beyond the trailing edge of the airfoil and lead to unsteady attachment and consequently to a time-periodic variation in vorticity flux and in circulation. In contrast, the suppression of separation at high actuation frequencies [i.e., St = O(10)] is marked by the absence of organized vortical structures along the flow surface. Finally, the dynamics of the transient lift in controlled reattachment and separation are investigated using pulsed amplitude modulation of the actuation input.
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References
Ahuja, K. K. and Burrin, R. H. (1984). Control of Flow Separation by Sound. AIAA Paper 84–2298.
Amitay, M., Honohan, A., Trautman, M. and Glezer, A. (1997). Modification of the Aerodynamic Characteristics of Bluff Bodies using Fluidic Actuators. AIAA Paper 97–2004.
Amitay, M., Smith, B. L. and Glezer, A. (1998). Aerodynamic Flow Control using Synthetic Jet Technology. AIAA Paper 98–0208.
Amitay, M. and Glezer, A. (1999). Aerodynamic Flow Control of a Thick Airfoil Using Synthetic Jet Actuators. FEDSM99–6922, Proceedings of the 3rd ASME/JSME Joint Fluids Engineering Conference, San Francisco, California.
Amitay, M., Kibens, V., Parekh, D. E. and Glezer, A. (1999). Flow Reattachment Dynamics over a Thick Airfoil Controlled by Synthetic Jet Actuators. AIAA Paper 99–1001.
Bar-Sever, A. (1989). Separation control on an airfoil by periodic forcing., AIAA J. 27 (6), 820–823.
Chang, R.-C., Hsiao, F.-B., and Shyu, R.-N. (1992). Forcing Level Effects of Internal Acoustic Excitation on the Improvement of Airfoil Performance. Journal of Aircraft 29 (5), 823–829.
Donovan, J. F., Kral, L. D. and Cary, A. W. (1998). Active Flow Control Applied to an Airfoil“. AIAA Paper 98–0210.
Erk, P. (1997). Separation Control on a Post-Stall Airfoil Using Acoustically Generated Perturbations. Ph.D. Dissertation, Technische Universitat Berlin, Germany.
Hsiao, F.-B., Liu, C.-F., and Shyu, J-Y. (1990). Control of Wall-Separated Flow by Internal Acoustic Excitation. AIAA Journal 28 (8), 1440–1446.
Hsiao, F.-G., Shyu, R.-N., and Chang, R.-C. (1994). High Angle-of-Attack Airfoil Performance Improvement by Internal Acoustic Excitation. AIAA Journal 32 (3), 655–657.
Huang, L. S., Maestrello, L. and Bryant, T. D. (1987). Separation Control over an Airfoil at High Angles of Attack by Sound Emanating from the Surface. AIAA Paper 87–1261.
Seifert, A., Bachar, T., Koss, D., Shepshelovich, M. and Wygnanski, I (1993). Oscillatory Blowing: A Tool to Delay Boundary-Layer Separation. AIAA Journal 31 (11), 2052–2060.
Seifert, A., Darabi, A., and Wygnanski, I. (1996). Delay of Airfoil Stall by Periodic Excitation. Journal of Aircraft 33 (4), 691–698.
Smith, B. L. and Glezer, A. (1998). The Formation and Evolution of Synthetic Jets. Physics of Fluids, Vol. 10, No. 9.
Smith, D. R., Amitay, M., Kibens, V., Parekh, D. E. and Glezer, A. (1998). Modification of Lifting Body Aerodynamics using Synthetic Jet Actuators. AIAA Paper 98–0209.
Williams, D., Acharya, M., Bernhardt, J., and Yang, P. (1991). The Mechanism of Flow Control on a Cylinder with the Unsteady Bleed Technique. AIAA Paper 91–0039.
Zaman, K. B. M. Q., Bar-sever, A., and Mangalam, S. M. (1987). Effect of Acoustic Excitation on the Flow over a Low-Re Airfoil. Journal of Fluid Mechanics, Vol. 182, 127–148.
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Amitay, M., Glezer, A. (2003). Separation Control using Synthetic Jet Actuators. In: Karagozian, A.R., Cortelezzi, L., Soldati, A. (eds) Manipulation and Control of Jets in Crossflow. International Centre for Mechanical Sciences, vol 439. Springer, Vienna. https://doi.org/10.1007/978-3-7091-2792-6_21
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DOI: https://doi.org/10.1007/978-3-7091-2792-6_21
Publisher Name: Springer, Vienna
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