Experimental study of a turbulent natural convection flow in a cubic enclosure with a large inner block partially heated

In this study, a turbulent natural convection flow occurring inside a closed cavity is investigated. The top, bottom, front and back walls of the cavity are adiabatic whereas the two other vertical walls are at imposed temperature (equal to the ambiant temperature of the room). A large inner block is placed inside the cavity. A vertical face of this block is heated, inducing a natural convection flow. The dynamical behavior of the flow is investigated using Particle Image Velocimetry and its thermal behavior using micro-thermocouples. Boundary layers, recirculation zones and instabilities developing inside the cavity are highlighted and discussed. A focus is made on a boundary layer instability of Tollmien-Schlichting type and the subsequent formation of an oscillating buoyant jet.