尾部隔板影响圆柱绕流场的二维层流数值模拟

为了探讨尾部隔板对圆柱绕流场的影响,采用有限体积法、非结构化网格和层流模型求解二维不可压缩N-S方程.在雷诺数为200的条件下,对背流面沿流动方向的对称线上,带薄板的圆柱绕流场进行了数值模拟,得到了流场速度云图、斯特劳哈尔数及平均阻力系数随隔板长度的变化情况.研究结果表明:在圆柱尾部加入的隔板能有效改善旋涡的脱落情况,削弱尾迹区的能量耗散,同时降低绕流的斯特劳哈尔数.在板长与圆柱直径比为L/D≥7的情况下,加入的隔板使圆柱尾部的旋涡被拉伸为扁平结构并限定在隔板两侧,在扁平对涡的外侧形成类似流线型的流场结构;尾部的隔板也使绕流的阻力系数呈现下降的趋势,当L/D=7时,平均阻力系数下降了约40%.

Numerical Simulation of Two-Dimensional Laminar Flow around Circular Cylinder with Splitter Plate

In order to study the effect of splitter plate on flows past through a circular cylinder,the finite volume method,unstructured grids,and the laminar flow model were used to solve the two-dimensional incompressible N-S equation.A thin plate was placed along the horizontal centerline downstream of the circular cylinder,and the flow past this circular cylinder was simulated with a two-dimensional model at Reynolds number 200.The change in the contour of instantaneous velocity,Strouhal number,and the average drag coefficient with the plate length were then obtained.Numerical results indicate that the splitter plate can effectively suppress the vortex shedding of the cylinder,weaken the energy dissipation in the wake region,and reduce the Strouhal number.The vortices are confined to the sides of the plate stably and symmetrically,and the vortex shedding behind the circular cylinder disappear completely when the length of the splitter plate is seven times more than the diameter of the circular cylinder(i.e.,L/D≥7),then the flow field behind the circular cylinder changes into streamlines.Meanwhile,the drag coefficient continuously decreases along with the plate length.When the plate length is seven times the cylinder diameter,the drag coefficient decreases from 1.43 to 0.87,by about 40%.