Abstract： Taken the FalknerSkan solutions of boundary layer flow as basic flow, the coherent structure, which was induced by local micro vibration on boundary layer wall was investigated by direction numerical simulation to solve incompressible NavierStokes equation. The results show that the initial distribution area and amplitude of disturbance velocity for coherent structure are similar in boundary layer under zero or negative pressure gradients. Howerer, with the evolvement of coherent structures, amplitude of disturbance velocity, high and low speed streaks, shear stress at wall surface, streamwise vortices and Reynolds stress distribution show obvious difference under different adverse pressure gradients. The disturbance induced by local micro vibration on the wall represents the form of coherent structures in boundary layer, and the strength and area of coherent structures increase with the increasing of adverse pressure gradient. The mean velocity profile becomes plumper near the wall with strong streamwise vortices to result drastic exchange of monentums and kinetic energy between inner and outer flow layers. Some dynamics characters of coherent structures display a certain extent consistency between turbulent and lamina flow.
2011, Vol. 32 
