Abstract
A two-dimensional laminar wake is formed behind a strip of metal screen. Due to the flow through the screen no dead water region is formed. The wake is excited by sound from a loudspeaker. The natural transition is simulated by the introduction of band noise of which frequency lies in the region of high linear growth. After the linear growth random low-frequency components are generated by the nonlinear interaction. Since the components have maximum intensity on the center line, the randomization seems to start there. The energy diffuses in the spectral space following frequency combination law. The spectrum changes gradually into continuous and smooth form. By the introduction of sound with two frequencies large-scale ordered motions are produced in the wake.
