Investigation of sediment transport processes due to geophysical flows

Alhusban, Zaid (2020) Investigation of sediment transport processes due to geophysical flows. PhD thesis, University of Glasgow.

Abstract

Despite the fact that sediment transport has been studied for decades, there is still a need to gain a further insight on the nature and driving mechanisms of bed particle motions induced by turbulent flows in the low transport stages (above the threshold of motion and below the continuous transport).

This study focuses on the design, development, calibration use of a novel tool for obtaining a better understanding of sediment transport dynamical processes which is an instrumented particle equipped with micro-electomechanical sensors (MEMS). To that goal particle transport experiments were conducted at a laboratory flume under a range of well-controlled above the threshold of motion flow conditions. Combinations of two hydraulically rough bed surfaces, 5 flow rates and 4 instrumented particle densities, have been tested to assess the effects of changing flow rates and particle densities on its transport dynamics using indicators such as the number of particle hops per second (as derived from processing raw recordings of the sensor data). The time and frequency domain analysis help identifying the dominant (most frequently occurring) frequencies of inter-particle collisions as well as the particle hop length, hop travel duration and instantaneous particle velocity.

The sensor data were used to calculate the kinetic energy for a range of sets of sediment transport experiments with varying flow rates and particle densities, so the probability distribution functions (PDFs) of particle transport features, such as particle’s total energy, are generated, which give information about particle interaction with the bed surface during its motion. In addition, the mode of transport obtained from the sensor results can be validated by using top and side cameras, respectively.

In general, the response of the instrumented particle for a range of experiments showed logical and satisfactory results so it demonstrated its capability of recording inertial dynamics due to flow turbulence. As a result, it can be a useful tool in providing a better understanding of how local hydrodynamic conditions may instantaneously induce different particle interactions with the bed surface, eventually resulting in different transport rates.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Hydraulics, sediment transport, river engineering.
• Colleges/Schools: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Supervisor's Name: Valyrakis, Dr Manousos
• Date of Award: 2020
• Embargo Date: 24 June 2023
• Depositing User: MR Zaid Alhusban
• Unique ID: glathesis:2020-81482
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 24 Jun 2020 16:17
• Last Modified: 25 Jun 2020 06:46
• URI: https://theses.gla.ac.uk/id/eprint/81482