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This technical paper offers an alternative method to the traditional physical geography course which has as its primary objective the knowing of approved body of knowledge. The premise is that a discipline of physical geography does not now exist and that traditional physical geography consists of nearly independent topics treated without common process or methodology. The suggested alternative interface system, defined as the study of the workings of the environment at the interface at the bottom of the atmosphere, focuses on the role of location or "place" in the different work accomplishments of environment and upon work allocation and budgeting. The unifying focus of this alternative is the timing (and, eventually, the amounts) of these work accomplishments -- energy flows and conversions--by systems which share the energy and material endowments of the interface, where man's enterprises are found. Physical systems and society's dependence and effects on them are both included in the alternative. In conclusion, it is suggested that the proposed alternative to physical geography could provide the basis for a unifying discipline if a significant number of physical geographers report work accomplishments of environmental systems. (Author/SJM)

The fluid dynamics in the far-field of liquid sprays involves a wide range of spatio-temporal scales; challenging experimental observation and numerical modeling alike. Here we show how a combination of multiple imaging approaches, targeted to different scales, can provide useful insight into this class of flows. We performed multi-scale imaging measurements in the far-field of an upward-facing liquid spray issued into a large quiescent air chamber by a hollow-cone atomizer. Time-resolved planar laser imaging was carried out simultaneously over two nested windows: one aimed at the large-scale dynamics of the spray cone, and the other focused on the intermediate-scale motions spanning the cone half-width. Spray velocity fields were obtained from both windows via Particle Image Velocimetry (PIV) using robust phase correlation and multi-frame pyramid correlation. Additionally, Lagrangian droplet trajectories were obtained in the intermediate-scale window via Particle Tracking Velocimetry (PTV). Finally, droplet sizes and velocities were obtained via shadowgraphy using a double-pulsed LED source over a small-scale (cm-sized) window. We discuss the agreement between the different techniques, as well as the physical insight offered by the combined measurement approaches on various aspects of the flow, including: velocity self-similarity, correlated and uncorrelated motion, frequency content, and droplet size-velocity correlation. © 2020 Elsevier Ltd., International Journal of Multiphase Flow, 132, ISSN:0301-9322, ISSN:1879-3533