TURBULENCE TRANSITION THRESHOLD OF A BUOYANCY-DRIVEN FLOW OVER AN ISOTHERMAL VERTICAL WALL

The integral formalism has been developed in an attempt to predict the mathematical transition threshold from laminar to turbulent regimes in a free convection boundary-layer flow adjacent to an isothermal vertical wall and also to gain a better understanding in the prediction of the turbulence mechanism. The transition threshold is approached herein as the intersection of two fully developed laminar and turbulent flow regimes. The transition for the isothermal wall condition is the Prandtl number dependent and occurs differently depending on whether the dynamical or thermal viewpoints are considered. A change in the transition threshold behaviour is observed at Pr = 20.