Experimental Study on the Evolution Characteristics of Sand-Laden Vortex Based on Energy Gradient Theory

A sand-laden vortex is a common phenomenon in marine engineering, particularly in coastal near-bed water intake and pumping facilities, and is widely recognized as an unfavorable factor affecting the safe and efficient operation of hydraulic machinery. The purpose of this study is to explore the energy characteristics of the development process of a sediment-laden vortex in the inlet pool. The research method is to use the V3V (Three-Dimensional Velocity Measurement System) to measure the three-dimensional velocity field of a sand-laden vortex, and analyze the energy characteristics of the evolution process of a sand-laden vortex in combination with energy gradient theory. The results indicate that in the early stage of vortex development, the turbulent kinetic energy of the sand-laden vortex gradually increases with time. After reaching its maximum value, the turbulent kinetic energy of the sediment-laden vortex continues to develop for about 0.4 s, then sharply decreases and completely dissipates within 0.3 s. The axial development speed of the vortex is closely related to the distance from the pump impeller. The energy gradient during the vortex evolution process indicates that the energy around the sand-laden vortex at different stages accumulates and dissipates as the vortex evolves. The research results of this article provide mechanistic insights into the evolution of a sand-laden vortex and offer theoretical support for sediment control and hydraulic optimization in marine and coastal pumping systems.