Combustion of Methane in Countercurrent Shear Layers David Forliti, Department of Mechanical and Aerospace Engineering, The State University of New York at Buffalo, Buffalo, NY, 14260. The growth rate for reacting countercurrent shear layers as a function of velocity ratio shows that the growth decreases with increasing velocity ratio, a trend that is the opposite as that found for nonreacting shear layers. It is hypothesized that the entrainment ratio dependency on the velocity ratio is responsible for altering the flame position within the shear layer, resulting in the observed trend. A transient dynamic has been observed where the secondary flow is intermittently experiencing transport of hot combustion products from the shear layer, altering the entrainment process. Further studies are underway to explore this mechanism. Combustion confined to mixing layer Diluted Fuel 2 cm Connect to suction system 5-20 cm Ambient air The growth rate of the shear layer is dramatically reduced as the primary stream equivalence ratio increases. This effect is likely caused by a an influence of the equivalence ratio on the location of the flame within the shear layer.