Capturing Free Surface Dynamics of Flows over a Stepped Spillway Using a Depth Camera

Sensors, vol. 25, pp. 2525

Abstract

RealSense™ D455, to capture detailed water surface measurements of a highly turbulent, self-aerated flow in the case of a stepped spillway. Ambient lighting conditions and various sensor settings, including configurations and parameters affecting data capture and quality, were assessed. A free surface profile was extracted from the 3D measurements and compared against phase detection conductivity probe (PDCP) and ultrasonic sensor (USS) measurements. Measurements in the non-aerated region were influenced by water transparency and a lack of detectable surface features, with flow depths consistently smaller than USS measurements (up to 32.5% less). Measurements in the clear water region also resulted in a "no data" region with holes in the depth map due to shiny reflections. In the aerated flow region, the camera effectively detected the dynamic water surface, with mean surface profiles close to characteristic depths measured with PDCP and within one standard deviation of the mean USS flow depths. The flow depths were within 10% of the USS depths and corresponded to depths with 80-90% air concentration levels obtained with the PDCP. Additionally, the depth camera successfully captured temporal fluctuations, allowing for the calculation of time-averaged entrapped air concentration profiles and dimensionless interface frequency distributions. This facilitated a direct comparison with PDCP and USS sensors, demonstrating that this camera sensor is a practical and cost-effective option for detecting free surfaces of high velocity, aerated, and dynamic flows in a stepped chute.

Authors 3

1. Megh Raj KC

   Utah State University

   Affiliation as printed

   Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, 8200 Old Main Hill, Logan, UT 84322-8200, USA

2. Brian Mark Crookston corresponding

   Utah State University

   Affiliation as printed

   Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, 8200 Old Main Hill, Logan, UT 84322-8200, USA

3. Daniel B. Bung Aachen Hydraulic Engineering Section (HES) Civil Engineering Department

   FH Aachen

   Affiliation as printed

   Hydraulic Engineering Section, Civil Engineering Department, FH Aachen University of Applied Sciences, 52066 Aachen, Germany