Abstract
A natural convection boundary-layer flow of an optically dense gray viscous fluid (liquid metal) above a horizontal circular disk with regard to thermal radiation is discussed. The radiative heat flux term is expressed by using the optically thick radiation limit. The corresponding boundary-layer equations are solved with the aid of three distinct numerical techniques: the straightforward finite difference (SFD) method is employed to solve the problem directly, and then the stream function formulation (SFF) and primitive variable formulation (PVF) methods based on solving transformed equations are used. The numerical results are interpreted in terms of the local skin friction coefficient and the local Nusselt number. The influence of the problem parameters on these characteristics is shown.