Distribution of a Trace Element in a Boundary Layer with Mass Transfer

摘要

A theory is presented for the downstream distribution of a tracer injected into a boundary layer of a flat plate or cone with self-similar mass transfer. The tracer, which is injected over a finite length of the surface is assumed to be chemically inert. Its behavior is controlled by a frozen diffusion equation. The assumption of constant density - viscosity product, and unit Schmidt number results in a linear partial differential equation for the seed mass fraction. It is shown that for downstream of the tracer injection region, the analytical results reduce to a simple form; namely, the mass concentration profile is proportional to the local shear even in the presence of mass transfer. However, near the tracer injection region, even the first ten terms are insufficient to yield profiles comparable to those produced by a finite difference numerical integration scheme. (Author)