Introduction Axisymmetric bluffbodies are used to enhance mixing and stabilize combustion between two streams. They are frequently utilized in utility combustors and propulsion systems since they exhibit the desirable property of promoting mixing at the expense of small pressure loss. Nonreacting and reacting bluffbody flows have been a subject of extensive experimental investigation, include flows in liquids and gases, unconfined and confined flows, and largeand small-scale facilities. Experimental observations indicate that nonreacting and reacting bluffbody flows are unsteady and, in most cases, can be characterized by large-scale, periodic oscillations.