Asymptotic approximations for a singularly perturbed convection-diffusion problem with discontinuous data in a sector

  • Authors:
  • José L. López;Ester Pérez Sinusía

  • Affiliations:
  • Departamento de Matemática e Informática, Universidad Pública de Navarra, 31006-Pamplona, Spain;Departamento de Matemática e Informática, Universidad Pública de Navarra, 31006-Pamplona, Spain

  • Venue:
  • Journal of Computational and Applied Mathematics
  • Year:
  • 2005

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Abstract

We consider a singularly perturbed convection-diffusion equation, -@e@Du+v-.@?-u=0 on an arbitrary sector shaped domain, @W={(r,@f)|r0,00^+ (with fixed distance r to the discontinuity point of the boundary condition) and (b) when that distance r-0^+ (with fixed @e). It is shown that the first term of the expansion at @e=0 contains an error function. This term characterizes the effect of the discontinuity on the @e-behaviour of the solution and its derivatives in the boundary or internal layers. On the other hand, near discontinuity of the boundary condition r=0, the solution u(r,@f) of the problem is approximated by a linear function of the polar angle @f.