Dynamic Lift and Vortex Breakdown during an Unsteady Flow over a Pitching Airfoil

Authors

  • Ales Svoboda University of Defence in Brno, Czech Republic
  • Dalibor Rozehnal University of Defence in Brno, Czech Republic

DOI:

https://doi.org/10.3849/aimt.01227

Keywords:

unsteady aerodynamics, dynamic lift, vortex, pitching, airfoil, NACA 0012, CFD

Abstract

Computational fluid dynamics techniques are used to give a detailed insight into unsteady phenomena taking place in the vicinity of a pitching airfoil. The vortex formation and breakdown are analyzed using the time history of pressure distribution, vorticity and injected massless particle trajectories. Different cases of flows are modeled to determine the effect of reduced frequency on unsteady lift. Finally, a comparison of lift coefficients for steady and unsteady cases is provided.

References

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ROZEHNAL, D. and SVOBODA, A. Unsteady Measurement of Aerodynamic Characteristics of a Profile During Dynamic Stall [Internal Report]. Brno: University of Defence, K‐204/A, 2008.

LOWSON, M. Some Experiments with Vortex Breakdown. The Aeronautical Journal, 1964, vol. 68, no. 641, p. 343-346. ISSN 0001-9240

KRISHNAMOORTHY, V. Vortex Breakdown and Measurements of Pressure Fluctuations over Slender Wings [Ph.D. thesis]. The University of Southampton, 1966.

WOODGATE, L. Measurements of the Oscillatory Pitching-Moment Derivatives on a Sharp-Edged Delta Wing at Angles of Incidence for Which Vortex Breakdown Occurs. Aeronautical Research Council, R.&M. 3628, Part III, 1971.

WOLFFELT, K. Investigation on the Movement of Vortex Burst Position with Dynamically Changing Angle of Attack for a Schematic Delta Wing in a Water Tunnel with Correlation to Similar Studies in Wind Tunnel, Aerodynamic and Related Hydrodynamic Studies Using Water Facilities. AGARD-CP-413, 1987.

ATTA, R. and ROCKWELL, D. Hysteresis of Vortex Development and Breakdown on an Oscillating Delta Wing. AIAA Journal, 1987, vol. 25, no. 11, p. 1512-1513. ISSN 0001-1452.

ATTA, R. and ROCKWELL, D. Leading-edge Vortices due to Low Reynolds Number Flow Past a Pitching Delta Wing. AIAA Journal, 1990, vol. 28, no. 6, p. 995-1004. ISSN 0001-1452.

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Published

17-05-2018

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Section

Research Paper

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How to Cite

Dynamic Lift and Vortex Breakdown during an Unsteady Flow over a Pitching Airfoil. (2018). Advances in Military Technology, 13(2), 173-183. https://doi.org/10.3849/aimt.01227

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