Turbulent shear-layer mixing at high Reynolds numbers: effects of inflow conditions

• Published in: Journal of fluid mechanics 1998-12, Vol.376, p.115-138
• Main Authors: SLESSOR, M. D., BOND, C. L., DIMOTAKIS, P. E.
• Format: Article
• Language: English
• Subjects: Chemically reactive flows; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); High-reynolds-number turbulence; Physics; Reactive, radiative, or nonequilibrium flows; Turbulent flows, convection, and heat transfer
• ISSN: 0022-1120; 1469-7645
• DOI: 10.1017/S0022112098002857

We report on the results from a set of incompressible, shear-layer flow experiments, at high Reynolds number (Reδ≡ρΔUδT(x)/ μ≃2×105), in which the inflow conditions of shear-layer formation were varied (δT is the temperature-rise thickness for chemically-reacting shear layers). Both inert and chemically-reacting flows were investigated, the latter employing the (H2+NO)/F2 chemical system in the kinetically-fast regime to measure molecular mixing. Inflow conditions were varied by perturbing each, or both, boundary layers on the splitter plate separating the two freestream flows, upstream of shear-layer formation. The results of the chemically-reacting ‘flip experiments’ reveal that seemingly small changes in inflow conditions can have a significant influence not only on the large-scale structure and shear-layer growth rate, as had been documented previously, but also on molecular mixing and chemical-product formation, far downstream of the inflow region.