| dc.description.abstract | This study investigates the behavior of particle flow in a two-phase localized dam-break flow under different saturation conditions, with a detailed analysis of particle flow and deposition phenomena. The experiments were conducted using a quasi-two-dimensional horizontal flume, measuring 120 cm in length, 10 cm in width, and 50 cm in height. Prepared particle columns with the same initial aspect ratio were used, and the baffle was quickly removed using an air cylinder to simulate a dam-break scenario. High-speed cameras captured the dynamic process of particle collapse, and image processing analysis was performed. Additionally, Particle Image Velocimetry (PIV) was employed to calculate the velocity field distribution during particle flow. The experimental results were analyzed by examining the profiles of particles and interstitial fluid at different characteristic times, studying the particle runout distance and descent distance, calculating the front velocity and descent velocity of particles, and investigating the collapse duration. Furthermore, the open-source software PIVlab was used to analyze the velocity field distribution at each characteristic time to determine the area of the flowing layer, thereby understanding the variations in particle flow behavior under different saturation levels, interstitial fluid viscosities, and gate openings.
The experimental results indicate that different liquid saturation levels, interstitial fluid viscosities, and gate openings significantly impact the flow behavior of two-phase particle collapse. As liquid saturation increases, particle runout distance, descent height, and velocity all show significant improvement, indicating that the presence of liquid reduces cohesion between particles, promoting their flow and dispersion. An increase in gate opening leads to more particles and liquid mixture passing through the gate, resulting in an increase in runout distance, while descent height and velocity initially increase and then decrease, and the collapse duration is shortened accordingly. With increasing interstitial fluid viscosity, runout distance decreases relatively, but the difference is not significant under supersaturated conditions due to the greater influence of liquid potential energy, which weakens the impact of viscosity on runout distance. Descent height and velocity decrease with increasing viscosity in both unsaturated and supersaturated states. In the saturated state, a special situation is observed where the descent velocity of the glycerol-water solution is slower, but its descent height is greater than that of water. This is because high-viscosity fluid affects particle motion, allowing particles to remain in motion for a longer time, thereby increasing the final descent height, while the initial particle motion velocity is relatively lower due to greater fluid resistance. Finally, from the velocity field profiles, significant differences in flow behavior among different experimental groups were observed, including variations in velocity magnitude and velocity vectors. These data analyses allowed for a comparison of the flowing layer areas to quantify the dynamic behavior of particles and interstitial fluids in each experimental group. | en_US |