An interferometric study of the local heat transfer by natural convection in inclined airfilled enclosures

A holographic interferometer is used to measure the local heat transfer by natural convection in an inclined air-filled enclosure with isotherm hot and cold walls and adiabatic side walls. The air layer is heated from below. It is shown that at an angle of inclination greater than 40 deg the local Nusselt number is maximum at the lower side and minimum at the upper side of the hot plate. At an angle of inclination less than 30 deg, the local Nusselt number has several maxima and minima at different locations along the hot plate. With decreasing angle of inclination, the local heat transfer decreases at the lower side while it increases at the upper side. Mean Nusselt number increases with decreasing angle of inclination for all Rayleigh numbers considered.