Author(s): M. Y. Lam; H. W. Liu; M. S. Ghidaoui
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Keywords: Keywords: Shallow mixing layers; Large scale horizontal vortices; Secondary subharmonic resonance
Abstract: The process of vortex merging in shallow mixing layers is studied numerically with a temporal simulation which solves the shallow water equations. A simple simulation with the initial velocity profile perturbed with the fundamental wavenumber and the subharmonic wavenumber is performed. Preliminary results show that the pairing of the large scale horizontal vortices can be explained with the secondary subharmonic resonance in the notion of two-dimensional incompressible mixing layers. The secondary subharmonic resonance is the excitation experienced by the subharmonic due to the instability of the base flow being a shear layer with a roll of vortices at the center. The Stuart solution, which represents such a base flow, is also fitted with the numerically simulated vortices of the fundamental wavenumber, preparing for a linear stability analysis with the base flow of the Stuart solution in future work.
Year: 2011