Cellular instabilities, sublimit structures and edge-flames in premixed counterflows

We examine twin premixed flames in a plane counterflow and uncover, in the parameter space, a hitherto unknown domain of cellular instability. This le ads us to hypothesize that for small Lewis numbers a two-dimensional (2D) s teady solution branch bifurcates from the one-dimensional (1D) solution bra nch at a neutral stability point located near the strain-induced quenching point. Solutions on this 2D branch are constructed indirectly by solving an initial-value problem in the edge-flame context defined by the multiple-va lued bistable 1D solution. Three kinds of solution are found: a periodic ar ray of dame-strings, a single isolated flame-string and a pair of interacti ng flame-strings. These structures can exist for values bf strain greater t han the 1D quenching value, corresponding to sublimit solutions.