Abstract
Edgetone phenomenon is computationally simulated using the two-dimensional compressible Navier-Stokes equations with high-order compact finite difference scheme and Runge-Kutta time integration scheme. Flow features obtained in the present computations agree well with that obtained in the experiment in the past. The results show that the edgetone frequency decreases with jet Mach number. This indicates that compressibility effect exists in the edgetone phenomenon, which justifies the feedback-loop mechanism proposed in the past. Detailed analysis of convective velocities of the jet disturbance is then conducted. There exists non-linearity; the convective velocities are high near the jet exit and low near edge. The result indicates that the value 0.25 proposed by Powell as a phase-lag parameter based on the assumption of constant disturbance velocity includes this non-linear effect, and the value of the real phase-lag parameter becomes -0.2 when considering non-linearity.
