In laminar jet flow, mixing is often a problem. The absence of small scale structures makes it hard to foresee anything else but mixing by diffusion. However, as shown by this study, adding an amount of swirl significantly enhances mixing in an annular jet flow with Re=180. Applications that need turbulent-like flow features such as mixing, or centrifugal forces that usually are associated with higher Reynolds numbers, are being modeled in a laminar regime. The flow features arising from this flow state are simulated with a 3D grid using the direct numerical simulation approach with a proper grid independence study. Velocity fields and turbulence parameters are presented. The velocity field is also measured with Stereo Particle Image Velocimetry (SPIV) experiments. The results of the simulation and the experiments are compared and assessed in terms of first and second order statistics.

Keywords: Turbulence, Experimental techniques, Computational methods