Nonlinear Wave Motions in Stratified Boundary Layers

Denier, James P.; Stott, Jillian A. K.; Mureithi, Eunice

doi:10.1007/s001620050053

Cited by 1 publication

(2 citation statements)

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“…Buoyancy effects are more dominant in flows with no free-stream pressure gradient. The velocity overshoot causes the flow to have points of inflexion, thus rendering the basic flow susceptible to inviscidly unstable short wavelength disturbances as has been detailed by Denier et al (1997).…”

Section: Resultsmentioning

confidence: 98%

“…The current study aims to explore absolute/convective instability in mixed forced-free convection boundary-layer flow over a horizontal surface. This study has been prompted by results obtained in temporal stability studies of mixed forced-free convection boundary layers by Denier and Mureithi (1996), Denier et al (1997), Mureithi et al (1997) and Mureithi and Mason (2002). Such boundary layers were found to be characterized by internal regions of 'supervelocities' due to acceleration of the boundary-layer flow by a buoyancy-induced pressure gradient.…”

Section: Introductionmentioning

confidence: 99%

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Absolute-convective instability of mixed forced-free convection boundary layers

Mureithi¹,

Denier²

2010

Fluid Dyn. Res.

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A spatio-temporal inviscid instability of a mixed forced-free convection boundary layer is investigated. The base flow considered is the self-similar flow with free-stream velocity u e ∼ x n . Such a boundary-layer flow presents the unusual behaviour of generating a region of velocity overshoot, in which the streamwise velocity within the boundary layer exceeds the free-stream speed. A linear stability analysis has been carried out. Saddle points have been located and a critical value for the buoyancy parameter, G 0c ≈ 3.6896, has been determined below which the flow is convectively unstable and above which the flow becomes absolutely unstable. Two spatial modes have been obtained, one mode being convective in nature and the other absolute. The convective-type spatial mode shows mode crossing behaviour at lower frequencies. Thermal buoyancy is shown to be destabilizing to the absolutely unstable spatial mode.

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Section: Resultsmentioning

confidence: 98%