Flow features of confined swirling jets

New features of swirling jets

Important new features are found for a family of swirling jets with velocity v;z, where z is the distance from the jet origin. First, there is a sharp minimum of the pressure coefficient at a certain value of the swirl number Sw which is nearly n independent; this feature can be utilized in technological devices. Second, as Sw increases, a separation zone develops, where the fluid is not at res...

Experimental Study of Unconfined and Confined Isothermal Swirling Jets

Abstract—A 3C-2D PIV technique was applied to investigate the swirling flow generated by an axial plus tangential type swirl generator. This work is focused on the near-exit region of an isothermal swirling jet to characterize the effect of swirl on the flow field and to identify the large coherent structures both in unconfined and confined conditions for geometrical swirl number, Sg = 4.6. Eff...

Numerical Simulation of a Confined Swirling Flow in a Model Gas Turbine Combustor

Sidewall boundary layer instabilities in confined swirling flow †

We examine enclosed swirling transitional and turbulent flows in a cylindrical vessel, driven by a single rotating endwall. The cylinder height:radius ratio H/R = 1 was chosen explicitly to preclude the possibility of vortex breakdown on the cylinder axis, thus concentrating attention on the behaviour of the cylindrical sidewall boundary layers. Over a range of Reynolds numbers above Re = ΩR2/ν...

Axisymmetric vortex breakdown Part 1. Confined swirling flow

A comparison between the experimental visualization and numerical simulations of the occurrence of vortex breakdown in laminar swirling flows produced by a rotating endwall is presented. The experimental visualizations of Escudier (1984) were the first to detect the presence of multiple recirculation zones and the numerical model presented here, consisting of a numerical solution of the unstead...