An investigation of the behaviour of planar jets using a time accurate fractional step scheme

Abstract

The transition behaviour of planar jets has been the subject of extensive investigation, using both numerical and experimental approaches. It is well known that above a critical Reynolds number the jet will exhibit a sinusoidal, flapping, bifurcation. Numerical simulations of planar jet flow have been carried out using a time accurate fractional step Navier-Stokes solver defined on a non-staggered grid. Results have been obtained for a range of Reynolds numbers to investigate the bifurcation and stability characteristics of the flow and to obtain the critical Reynolds number for the onset of unsteadiness. This critical Reynolds number is found to be in good agreement with that obtained experimentally and for a non-parallel Bickley jet using a semi-analytic stability technique, whereas earlier parallel stability results considerably under-predict this value. The numerical method is described and results presented detailing the character and behaviour of the steady and bifurcated flow together with comparisons to previous investigations.