The vertical upward Taylor flow regime has been extensively studied at the capillary and large channel scale limits. However, flow behavior at the intermediate scale (5 less than or similar to Bo less than or similar to 40, or 6 mm less than or similar to D less than or similar to 17 mm for ambient gas-water flows) is comparatively poorly characterized. This regime is fundamentally different because classes of forces conventionally associated with either small or large Bond number flows are all relevant. In this investigation, air-water Taylor-flow experiments are conducted in 6.0, 8.0, and 9.5 mm diameter tubes. High-speed video data are collected, and automated image analysis algorithms are developed to measure flow parameters including: bubble rise velocity, liquid film thickness, void fraction, and Taylor bubble and liquid slug lengths. New correlations and flow models are developed to predict these parameters at the intermediate scale. Results from this study enable kinematic closure of intermediate scale Taylor flows. (C) 2015 Elsevier Ltd. All rights reserved.