Navier-Stokes Computations of Three-Dimensional Laminar Flows with Buoyancy in a Channel with Wing-Type Vortex Generators

Abstract

Longitudinal vortices embedded in shear flows can substantially increase the heat transfer between the fluid and the channel wall by inducing azimuthal velocity which mixes continuously hot and cold fluids [1]. This technique of heat transfer enhancement is of special interest in channel flows where the heat transfer between the fluid and channel walls detiorates as the boundary layer grows on the channel walls and the flow tends to become fully developed. Longitudinal vortices can be generated in the channel flows by mounting vortex generators on the channel wall. Alternatively part of the channel wall can be used as vortex generators. To this purpose small rectangular or triangular pieces can be punched out of the channel wall. These pieces will remain attached to the channel wall at the base and project into the flow with an angle of attack β with the main flow direction. The longitudinal vortices are generated along the side edge of the vortex generator due to the pressure difference between front surface facing the flow and the back surface of the vortex generator.