A finite element analysis of steady viscous flow in triangular cavities

Abstract

A finite element formulation of the Navier—Stokes equations, written in terms of the stream function, ψ, and vorticity, ω, for a Newtonian fluid in the absence of body forces, is used to solve the problem of flow in a triangular cavity, driven by the uniform motion of one of its side walls. A key feature of the numerical method is that the difficulties associated with specifying ω at the corners are addressed and overcome by applying analytical boundary conditions on ω near these singularities. The computational results are found to agree well with previously published data and, for small stagnant corner angles, reveal the existence of a sequence of secondary recirculations whose relative sizes and strengths are in accord with Moffatt's classical theory. It is shown that, as the stagnant corner angle is increased beyond approximately 40°, the secondary recirculations diminish in size rapidly.