Abstract

We introduce a novel, cost-effective photogrammetry-based method designed for measuring rapidly evolving three-dimensional surface topography in particle-fluid flow experiments. This method offers high-resolution results over a considerable surface area, enabling the capture of dynamic flow events with temporal granularity limited only by removable memory card capacity. Multiple WiFi-enabled security cameras, meticulously calibrated with precision-measured reference points on calibration boards, are employed in this methodology. External synchronization, facilitated by strategically-positioned flash lamps, allows calibration among cameras without additional precise tools. Validating our method through an alluvial fan experiment showcases its efficacy in tracking the growth and evolution of experimental debris flows, particularly in capturing the dynamic evolution of debris flow deposits on a growing alluvial fan. This example illustrates the method's ability to link local flow, evolution, and deposition to multiple channel avulsion events, highlighting its success in capturing distinct slope and height dependencies associated with these phenomena. Overall, our method transcends conventional measurement approaches, providing a significant advancement in capturing the intricacies of rapidly evolving three-dimensional surface topography in particle-fluid flow experiments. Its cost-effectiveness and robustness make it a valuable tool for diverse, dynamic scenarios, presenting a promising solution for experimental laboratory-scale landscape studies.