Viscous Burgers equation driven by point source: a formula for the weak limit
Smritikana Pal, Manas R. Sahoo
TL;DR
This work analyzes the viscous Burgers equation driven by a point source and derives the weak vanishing-viscosity limit as $\epsilon\to0$. Via the Hopf–Cole transform, explicit viscous solutions on each side of the origin are obtained and linked by a boundary term, yielding tractable representations and a corresponding weak formulation. The vanishing viscosity limit is characterized by the minimum of three variational functionals on each half-line, producing explicit limit functionals $U_R$ and $U_L$ whose derivatives give the limiting velocity field. The limit $u(x,t)$ satisfies the inviscid equation $u_t+(u^2/2)_x=\delta$ in the distributional sense, establishing a rigorous connection between viscous regularization and a weak solution for a scalar balance law with a delta source and discontinuous flux.
Abstract
In this article, we obtain the weak limit of the solutions of the viscous Burgers equation driven by a point source term, as the coefficient of viscosity tends to zero. The weak limit is related to the variational problem that consists of three types of functional, which is not usual in the absence of the source term.
