RT Journal Article
T1 Non-Boussinesq stability analysis of natural-convection gaseous flow on inclined hot plates
A1 Rajamanickam, P.
A1 Coenen, Wilfried
A1 Sánchez, Antonio L.
AB The buoyancy-driven boundary-layer flow that develops over a semi-infinite inclined hot plate is known to become unstable at a finite distance from the leading edge, characterized by a critical value of the Grashof number Gr based on the local boundary-layer thickness. The nature of the resulting instabilitydepends on the inclination angle /, measured from the vertical direction. For values of / below a critical value /c the instability is characterized by the appearance of spanwise traveling waves, whereas for/ > /c the bifurcated flow displays Görtler-like streamwise vortices. The Boussinesq approximation,employed in previous linear stability analyses, ceases to be valid for gaseous flow when the wall-to-ambient temperature ratio Hw is not close to unity. The corresponding non-Boussinesq analysis is pre-sented here, accounting also for the variation with temperature of the different transport properties. Atemporal stability analysis including nonparallel effects of the base flow is used to determine curves ofneutral stability, which are then employed to delineate the dependences of the critical Grashof numberand of its associated wave length on the inclination angle / and on the temperature ratio Hw for the twoinstability modes, giving quantitative information of interest for configurations with Hw   1   1. Theanalysis provides in particular the predicted dependence of the crossover inclination angle /c on Hw ,indicating that for gaseous flow with Hw   1   1 spanwise traveling waves are predominant over a range of inclination angles 0 6 / 6 /c that is significantly wider than that predicted in the Boussinesq approximation.
PB Elsevier BV
SN 0017-9310
YR 2017
FD 2017-06
LK https://hdl.handle.net/10016/35617
UL https://hdl.handle.net/10016/35617
LA eng
DS e-Archivo
RD 1 may. 2024