Analysis of liquid spray with and without homogeneous background turbulence

We employ a large chamber of homogeneous turbulence in a recently introduced facility to experimentally investigate the properties of a liquid water spray produced by a hollow-cone nozzle. We characterize the properties of the spray issued in quiescent and turbulent air, and in particular: the spray penetration, its mixing with the surrounding air, the droplet size distribution, and the related Eulerian and Lagrangian two-point correlations. This is the first study in which spray dynamics are investigated over the full range of relevant scales with and without a turbulent background. To this end we perform planar imaging at various spatial and temporal resolutions. Focusing on a window in the far field, we perform particle tracking velocimetry using a high-speed laser and camera system, and droplet sizing by shadowgraphy using a low-speed high-resolution camera mounted on a long-range microscope and synchronized with a pulsed LED. The resulting spray penetration and flow characteristics for cases with and without background turbulence are discussed.