LAME interaction is an important phenomenon that occurs in a number of combustion technologies including gas turbines for both power generation and aircraft propulsion. Previous studies have shown that flame interaction causes changes in both the global and local flame behavior [1-3]. The time-averaged flame shape, flame static stability, and flame dynamic stability can vary with different levels of flame interaction. In this study, flame interaction is investigated using three interacting, planar, V-flames stabilized on triangular bluff bodies. Flameholders such as these are used in duct burners and afterburners. We have chosen this configuration to investigate fundamental flame and flow interaction processes as the configuration is largely two-dimensional, allowing for the use of planar diagnostics. The goal of this work is to compare the structure and turbulent characteristics of both the flow field and flame in a single-flame and multiple-flame configuration.

The time-averaged flow field around and behind a bluff body includes three important regions, as shown in Figure 1: the boundary layer along the bluff body, the separated free shear layer, and the wake [4, 5]. The boundary layer forms at the leading edge of the bluff body and develops until the separation points at the edges of the bluff body. The shear layers that develop from the separation points form the outer boundary of the recirculation zone, and interact further downstream. In the absence of combustion, the wake is subject to both the von-Karman and shear layer instabilities [6]. Combustion suppresses the von-Karman instability [7], provided the density ratio across the flame is sufficiently high, making the shear layer instability the dominant instability. This instability manifests itself as a symmetric billowing of the flame due to the symmetric vortex rollup. In the reacting flow the wake also transitions to a jet farther downstream due to the gas expansion across the flame.