关键词: 流体力学, 剪切来流, 流体控制, 圆柱绕流

Abstract: The boundary layer flow of cylinder can be modified effectively by Lorentz force near the surface of the cylinder in the weakly conductive fluid which holds the advantages for cylinder wake control. The experiment and calculation of cylinder wake and its electromagnetic control were investigated in the shear flow. Experiments were conducted in a rotating annular tank filled with a low-conducting electrolyte. A cylinder with electromagnetic actuators mounted on the surface was placed into the electrolyte. Force measurements were carried out by strain gages attached to a fixed beam to which the cylinder was suspended and flow fields were visualized by dye markers. Based on the Navier-Stokes equations considering the electromagnetic body force, i.e. Lorentz force, in the exponential-polar coordinates, the numerical investigations were carried out by means of an alternative-direction implicit alogorithm and a fast Fourier transform algorithm. The experimental and calculated results show that the cylinder wake leans towards the side of slow velocity of flow. The drag and lift vary periodically. The average value of lift is not 0 any longer, and its direction points to the side of slow velocity of flow. The wake becomes a line leaning to the side of slow velocity of flow under the action of Lorentz force. The drag decreases and doesn't oscillate any longer. The lift increases and turns to steady which points to the side of slow velocity of flow.

Key words: fluid mechanics, shear flow, flow control, cylinder wake