正弦波浪型平板对流动结构的控制

he present investigations focus attention on numerical simulations of three-dimensional flow around wavy rectangular slabs with sinusoidal variations in cross-section area along the spanwise direction at low Reynolds numbers of 100 and 500. The detailed near wake vortex structures of the wavy rectangular slab are captured and the influence of the wavy rectangular slab side ratio (L/Dm=1 to 8) is discussed compared with a straight rectangular slab with the same side ratio. Moreover, the pressure field, velocity field and force coefficients around the wavy surfaces are also calculated. The present numerical simulations show that the three-dimensional free shear layers behind the wavy rectangular slab are more stable than those of the straight rectangular slab. At L/Dm≥2, the free shear layers are even difficult to roll up into a mature vortex street behind the wavy slab at Re=100. The mean drag reduced with the r.m.s. lift of the wavy rectangular slabs being greatly suppressed compared with the straight rectangular slab for all side ratios at Re=500. A drag reduction of up to 32% at L/Dm=1 is obtained. It indicated that the wavy slab is capable of minimization of flow-induced vibration and drag reduction compared with the rectangular slab in cross flow conditions.