Measurements of molecular mixing have been conducted in subsonic, chemically -reacting, free-shear-layer flows. The base flows consisted of two freestreams of N2/He/Ar mixtures as diluents, at a nominal freestream speed ratio of U2/U1 = 0.4. The experiments were in the mixing-limited regime (high Damkoehler number limit), using the (H2+NO) / F2 chemical system. Previous data have suggested an approxi-mately 20% reduction in chemical-product volume fraction, per decade increase in Reynolds number.
The current investigation extended the Reynolds number range to 3.5x105, based on local shear-layer thickness and freestream velocity difference. The mixed-fluid fraction was estimated by a set of "flip" experiments. The new and previous data taken collectively suggest that the previously-documented decrease of product volume fraction, with increasing Reynolds number, persists to the highest Reynolds numbers investigated.