Author(s): Muhammad Zain Bin RIAZ; Shu-Qing YANG; Muttucumaru SIVAKUMAR

Linked Author(s): Muhammad Zain Bin Riaz

Keywords: tidal bore; drag force; lift force; laser Doppler anemometer; force transducer

Abstract:

The development of a bore in an open channel creates a sudden change in water surface elevation propagating upstream. In this study, physical modelling was performed to investigate both horizontal and vertical components of velocity and forces to clarify the mechanism of sediment initiation beneath a tidal bore. A laser Doppler anemometer, a highly sensitive force transducer, and ultrasonic displacement meters accompanied by video recordings were used to provide some quantitative data in terms of various force and velocity terms measured simultaneously acting on a targeted sphere. According to the experimental results, upward vertical force was the main force in destabilizing the particles however, a large upstream longitudinal force was found to be the dominant cause promoting upstream particle motion during the breaking roller passage. Furthermore, the forces were not only due to velocity but also to the sudden discontinuity in free water surface.

DOI: https://doi.org/10.25171/InstGeoph_PAS_Publs-2021-010

Year: 2021