SUMMARYCalculations of unsteady turbulent flow around and behind triangular-shaped flameholders using a finite volume code with a k--E model of turbulence are presented.The flow behind the flameholders is found to be unsteady (a von Kirman vortex street appears) with a well defined Strouhal frequency (predicted Sr =0.27 compared with an experimental value of 0.25). The predicted profiles of velocity and fluctuating kinetic energy agree well with experiments. The periodic motions in the vortex street are shown to be far more important than the turbulent stochastic motions in exchanging momentum in the transversal direction.The pressure-velocity coupling is handled with the SIMPLEC pressure correction procedure. The discretization in time is fully implicit and 90 time steps are used to resolve one time cycle. It was found that to capture the vortex street it is very important that the grid spacing is sufficiently fine (180 x 100).