Hydrodynamic stability analysis on inviscid cross sheared stratified flows
Conference Publication ResearchOnline@JCUAbstract
In this study, linear perturbation equations for CSS flows, in which two comparable orthogonal basic flow velocities (streamwise and spanwise velocities) coexist in a stratified environment, are derived in terms of a characteristic parameter, the cross shear ratio ξ=Δv0/Δu0, where Δu0 and Δv0 are the initial streamwise and spanwise velocity changes across the sheared layer, respectively. The stability features of a cross free sheared flow, a cross bounded sheared flow, and a cross jet flow with specific velocity and stratification profiles are obtained. The results show that the unstable regions of all these three types of CSS flows stretch towards large values of the local Richardson number Ri(g) with the introduction of the spanwise velocity, and the growth rate of the perturbation increases significantly when ξ increases. As a result of such a stretching effect, the stability boundary in terms of the critical local Richardson number Rig,cr expands with increasing ξ and exceeds Ri(g,cr) = 0.25, a value predicted by the classic Miles-Howard theorem.
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AFMC 2014: 19th Australasian Fluid Mechanics Conference
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978-0-646-59695-2
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4
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Melbourne, VIC, Australia
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Australasian Fluid Mechanics Society
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Clayton, VIC, Australia
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