Laser-Induced Fluorescence Technique for Measurement of Slot-Injected FluidConcentration Profiles in a Plate Turbulent Boundary Layer

摘要

A technique for measuring near instantaneous concentration profiles of a fluidinjected through a narrow inclined slot at the wall into a high unit Reynolds turbulent boundary layer is discussed. The concentration profiles are determined by measuring the light intensity emitted from a fluorescent dye premixed into the injectant flow as the injectant convects through an excitation laser beam. The fluorescence intensity is quantified by an electronically shuttered single stage microchannel plate image intensifier coupled to a linear photodiode array. This high resolution technique is being used to study the diffusion of injected polymer solutions away from the near wall region in a flat plate turbulent boundary layer where these solutions are effective in reducing drag. Keywords: Reynolds turbulent boundary layer. (aw)