Rotating spiral edge flames in von Karman swirling flows

Experimental observations of rotating spiral flame edges formed during near -limit combustion of a downward-facing, polymethylmethacrylate disk spinnin g in quiescent air are reported. These flames exhibit similarities to patte rns commonly found in quiescent excitable media. The tail rotates rigidly w hile the tip executes a compound, meandering motion sometimes observed in B elousov-Zhabotinskii reactions. A model assuming a rigid-body rotation with a constant speed of propagation relative to the swirling gas flow generate d by the spinning disk predicts the observed spiral shapes well.