THE EFFECTS OF MAXIMUM DENSITY AND TEMPERATURE-DEPENDENT VISCOSITY ON THE STABILITY OF LAMINAR FREE CONVECTION ALONG A VERTICAL ISOTHERMAL PLATE
The stability of laminar natural convective boundary layer flow of cold water along an isothermal vertical flat plate was studied employing the linear stability theory. The effects of maximum density and temperature-dependent viscosity were examined. Various combinations of wall and ambient temperatures, with and without the buoyancy force reversals inside the thermal boundary layer, were considered. In particular, the flow from a wall at 0°C was considered in detail. The numerical results reveal that the critical Grashof number for the onset of instability may be discontinuous in the region where flow reversals occur. Temperature-dependent viscosity stabilizes the flow for a heated wall and destabilizes it for a cooled wall. Flow visualization studies for a vertical cylindrical ice surface are also reported for various ambient water temperatures up to 20°C.