IMA Journal of Applied Mathematics Advance Access originally published online on June 26, 2008
IMA Journal of Applied Mathematics 2009 74(1):35-45; doi:10.1093/imamat/hxn009
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A singular perturbation problem with discontinuous data in a cuboid


Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, 31006 Pamplona, Spain
Email: jl.lopez{at}unavarra.es
Email: ester.perez{at}unavarra.es
Received on September 10, 2007; Revision received September 10, 2007. Accepted on March 3, 2008
We analyse the asymptotic behaviour of the solution of a 3D singularly perturbed convection–diffusion problem with discontinuous Dirichlet boundary data defined in a cuboid. We write the solution in terms of a double series and we obtain an asymptotic approximation of the solution when the singular parameter
0. This approximation is given in terms of a finite combination of products of error functions and characterizes the effect of the discontinuities on the small
-behaviour of the solution in the singular layers.
Keywords: singular perturbation problem; discontinuous boundary data; asymptotic expansions; error function.