Numerical study of formation of longitudinal vortices in natural convection flow over horizontal and inclined surfaces

This paper presents a numerical study of the formation of longitudinal Vort ices in natural convection flow over horizontal and inclined plates. The cr iterion on the position marking on the onset of longitudinal vortices is de fined in the present paper. The results show that the onset position charac terized by the Grashof number depends on the Prandtl number, wave number, a nd the inclined angle phi from the horizontal. The flow is found to become more stable to the vortex mode of instability as the value of inclined angl e increases, owing to a decrease in buoyancy force in the normal direction. However, the Prandtl number has a destabilizing effect on the flow. The re sults of the present numerical prediction show a reasonable agreement with the experimental data in the literature. (C) 2001 Elsevier Science Ltd. All rights reserved.