On the Hydrodynamics and Heat convection of an Impinging External Flow upon a cylinder with Transpiration and Embedded in a Porous Medium

Abstract

This paper extends the existing studies of heat convection by an external flow<br><br>impinging upon a flat porous insert to that on a circular cylinder inside a porous medium.<br><br>The surface of the cylinder is subject to constant temperature and can include uniform or<br><br>non-uniform transpiration. These cylindrical configurations are introduced in the analyses<br><br>of stagnation-point flows in porous media for the first time. The equations governing steady<br><br>transport ofmomentum and thermal energy in porous media are reduced to simpler nonlinear<br><br>differential equations and subsequently solved numerically. This reveals the dimensionless<br><br>velocity and temperature fields of the stagnation-point flow, as well as theNusselt number and<br><br>shear stress on the surface of the cylinder. The results showthat transpiration on the surface of<br><br>the cylinder and Reynolds number of the external flow dominate the fluid dynamics and heat<br><br>transfer problems. In particular, non-uniform transpiration is shown to significantly affect<br><br>the thermal and hydrodynamic responses of the system in the circumferential direction.<br><br>However, the permeability and porosity of the porous medium are found to have relatively<br><br>smaller influences.