Free-surface turbulence in hydraulic jump breaking roller at low inflow Froude number

Abstract: A hydraulic jump occurs when a high-velocity supercritical flow in an open channel transitions suddenly to a subcritical flow. In this study, new experiments with low inflow Froude numbers (2.1 < Fr1 < 3.8) were conducted in a large-size facility using ultrasonic displacement meters and digital cameras. The study provided details of free-surface turbulent fluctuations in a hydraulic jump with relatively large Reynolds numbers (1.36E+5 < Re < 2.46E+5). A time series analysis of the water surface elevation of the roller and the fluctuations of the hydraulic jump toe perimeter was conducted. The results characterized the dynamic and unsteady nature of the breaking jump roller. The findings offer valuable insights for researchers and engineers to enhance their comprehension of the physical processes involved. Keywords: Hydraulic jump, instantaneous free-surface fluctuation, low Inflow Froude numbers, turbulence, free-surface turbulence