Non-Parallel Vortex Instability of Natural Convection Flow Over a Non-Isothermal Horizontal Flat Plate


An analysis is performed to study the vortex instability of laminar boundary-layer flow in natural convection over a horizontal flat plate with variable surface temperature, Tw(x) - T∞ = Axn. The analysis is based on the linear non-parallel flow model in which the steady main flow is treated as two-dimensional and account is taken of the streamwise dependence of the disturbance amplitude functions. Neutral stability curves as well as critical Grashof numbers and critical wave numbers are presented for Prandtl numbers of 0.7 ≤ Pr ≤ 100, over a range of the exponent values n from- sol1 3 to 1.0. For a given Prandtl number, the flow is found to become more stable to the vortex mode of instability as the value of the exponent n increases. However, fluids with a larger Prandtl number are found to be more susceptible to the instability than fluids with a lower Prandtl number. Results from the present non-parallel flow analysis are compared with available results from the parallel flow analyses and experiments. The streamwise variation of the disturbances is found to stabilize the flow. © 1991.


Mechanical and Aerospace Engineering

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Article - Journal

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© 1991 Elsevier, All rights reserved.

Publication Date

01 Jan 1991