Study of confinement effects in countercurrent shear layers

This investigation is concerned with entrainment issues associated with countercurrent shear layers in the presence of confinement. Heat release has a detrimental effect on the shear layer growth which in turn affects the mixing and entrainment into a shear layer. Previous studies have shown that non-reacting countercurrent shear layers have higher normalized turbulence levels, shear layer growth rates, and enhanced entrainment characteristics compared to co-flowing shear layers. The objective of the current project was to explore the effect of confinement on the turbulent and entrainment characteristics of the countercurrent shear layer and to determine the usage of confinement as a control technique to alter the entrainment ratio in a shear layer. The countercurrent shear layer is established by a momentum driven primary stream and suction driven secondary stream. Particle image velocimetry is employed as the diagnostic to obtain flow field measurements. This entrainment control technique by applying confinement could be used to create better mixing zones which may facilitate the design of compact combustion systems with increased efficiency and reduced environmental impact.