(Note: This paper was published in ACTA AERONAUTICA ATRONAITICA SINICA, Vol

(Note: This paper was published in ACTA AERONAUTICA ATRONAITICA SINICA, Vol. 16, No.6, Nov 1995, including English abstract. The journal is sponsored by Chinese Society of Aeronautics and Astronautics)
ANALYSIS OF UNSTEADY LEADING/SIDE-EDGE SEPARATED FLOW

Ji Zhou

(Center of Aerodynamics Design and Research, Northwestern Polytechnical University, Xi'an, 710072)

Yin Xieyuan

(Department of Mechanics, University of Science and Technology, Hefei, 230026)

Abstract With unsteady vortex-lattice method (VLM), impulsive starting and upward ramp motions at constant angular rate are calculated for delta and rectangular wings. The results include unsteady pattern of leading/side-edge vortex rollup and aerodynamic characteristics. Effects of the aspect ratio and angle of attack are analyzed. Simulation results show that the upward ramp motion can significantly restrain the vortex breakdown and increase the lift coefficient. Present results are in convincing accordance with available experiments.

Key words vortex lattice method, unsteady flow, delta wings, trapped vortices

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