Response of a Flat-Plate Cascade to Incident Vortical Waves

Acoustic resonances and trapped modes in annular plate cascades

“…Here N m (x) denotes the Bessel function of the second kind. For d/D = 1, the resonant trapped mode frequencies approach the resonant frequencies of a corresponding twodimensional plate cascade with periodic boundary conditions imposed at y = 0 and the duct perimeter y = Dπ as sketched, for example, in figure 1 of Ragab & Salem-Said (2007) Whereas in the experiment of Parker & Pryce (1974) the frequency of the first circumferential trapped mode m = 1 could only be excited by a loudspeaker mounted at an opening in the side of the duct, the second, third and fourth trapped modes were excited by vortices shed from the trailing edges of the plates. The fifth trapped mode m = 8 was apparently outside the domain of their measurement.…”

Large Eddy Simulation of the Interaction of Homogeneous Turbulence with a Flat-Plate Cascade

“…To validate the implementation of our code; we computed the unsteady loading and radiated acoustic pressure field from flat plates interacting with vortical structures. We considered two fundamental problems: (1) A linear cascade of flat plates excited by a vortical wave (gust) given by a 2D Fourier mode, Ragab and Salem-Said ( [45], [46]). and 2The parallel interaction of a finite-core vortex with a single plate.…”