NUMERICAL STUDIES ABOUT A SYMMETRIC VORTEX FLOW AROUND A SLENDER BODY AT HIGH INCIDENCE
细长体大迎角非对称涡流的数值研究

Numerical simulations of low-speed turbulent flows around a slender body are conducted to explore the effect of a minute nose geometrical disturbance on the formation and development of flow asymmetry. The result shows that the asymmetric flows observed in experiment are simulated successfully by the introduction of a small bump placed near the body apex. The asymmetric vortex structure grows gradually along the symmetry axis of the slender body, and the distribution of sectional side force takes the sinusoid character of variation. Disturbance energy presents exponential spatial growth from the tip until it reaches the saturation. Disturbance scale influences the size and the distribution of flow asymmetry. The flow asymmetry shows a single periodicity when the circumferential position of the single disturbance changes. Numerical results show that the asymmetric vortex flow originates from the spatial instability of the forebody wake induced by a small disturbance.