Vortex streets formed behind oscillating bluff bodies consist of arrays of groups of two, three, or four vortices classified as 2S, P+S, and 2P shedding modes, respectively. The prevailing dominant mode depends primarily on the amplitude and the frequency of the oscillation and on the Reynolds number. We investigate the effect of noise at the inflow on the stability of these vortex modes in lam...

This letter presents an experimental study on the tonal noise generated by a sharp-edged flat plate at low-to-moderate Reynolds number. Flow and far-field noise data reveal that, in this particular case, the tonal noise appears to be governed by vortex shedding processes. Also related to the existence of the tonal noise is a region of separated flow slightly upstream of the trailing edge. Hydro...

This paper addresses the vibration of a square section cylinder due to the alternate vortex shedding at moderate Reynolds number (3500). The numerical investigation is focused on the perturbation of the vortex shedding in order to decrease the amplitude of the vibrations at lock-in. By analyzing the unsteady flow results, we show that a control technique spatially localized at the surface of th...

An exponentially convergent observer is designed for a linearized Ginzburg-Landau model of vortex shedding in viscous flow past a bluff body. Measurements are restricted to be taken collocated with the actuation which is applied on the cylinder surface. The observer is used in conjuction with a state feedback boundary controller designed in previous work to attenuate vortex shedding. Simulation...

Generation of Alfvénic (magnetohydrodynamic) vortices by the interaction of compressible plasma flows with magnetic-field-aligned blunt obstacles is modeled in terms of magnetohydrodynamics. It is found that periodic shedding of vortices with opposite vorticity is a robust feature of the interaction in a broad range of plasma parameters: for plasma beta from 0.025 to 0.5, and for the flow speed...

and suppressing fluctuating amplitude of the dynamic wind loads acting on the test model. With 24 suction/jet holes evenly distributed over the cylindrical test model (i.e., the N13 design of the present study), the passive jet control method was found to be able to achieve up to 33.7 % in drag reduction and 90.6 % in fluctuating wind loading suppression, in comparison with the baseline case. T...

Above a critical velocity, the dominant mechanism of energy transfer between a moving object and a dilute Bose-Einstein condensate is vortex formation. In this paper, we discuss the critical velocity for vortex formation and the link between vortex shedding and drag in both homogeneous and inhomogeneous condensates. We find that at supersonic velocities sound radiation also contributes signific...

1 2 A general method based on adjoint formulation is discussed for the optimal control of distributed parameter systems (including boundary parameter) which is especially suitable for large dimensional control problems. Strategies for efficient and robust implementation of the method are described. A set of consistency checks are proposed for the validation of the adjoint code. The method is ap...