A discontinuous finite-element formulation for internal radiation problems

This article presents a discontinuous finite-element formulation for internal thermal radiation problems. In contrast to the conventional finite-element formulation, the discontinuous algorithm permits the discontinuity of field variables across the internal interelement boundaries and is useful for integral-differential equations describing thermal radiation in absorbing/scattering media. Mathematical formulation and numerical implementation are given. The convergence rate and local mesh adaptivity are discussed. Two approaches for coupling of the discontinuous and conventional methods for mixed heat transfer calculations are presented. Numerical results are given for internal radiation and combined conduction/radiation problems and are compared with analytical solutions whenever available.