Investigation of Ship-Induced Hydrodynamics and Sediment Suspension in a Heavy Shipping Traffic Waterway

Lilei Mao,Yimei Chen

doi:10.3390/jmse8060424

Abstract

In order to investigate the complex hydrodynamics and associated sediment movement resulting from the ship passages in heavy shipping traffic waterways, field measurements were performed in a heavy shipping traffic waterway. Based on the collected waves, flow velocity and water turbidity data, the analyses of the ship-induced hydrodynamics and associated sediment suspension phenomena were conducted. The low-frequency primary wave and high-frequency secondary wave were more pronounced for a barge and yacht in the wave structure, respectively, and contributed more to the flow velocity fluctuations and the bottom shear stress. The ship-induced bottom shear stress can cause significant suspended sediment concentration increase, and there is a correlation between the maximum suspended sediment concentration and maximum ship-induced drawdown height, which can provide a reference for the waterway management.

Highlights

For natural alluvial rivers, their morphological parameters will be adjusted under the constant incoming water flow and sediment, and eventually reach a dynamic or quasi-equilibrium state by altering the water flow, entraining and redepositing riverbed materials [1]
The results show that the suspended sediment concentration changes caused by the navigation ships have a correlation with the ship-induced drawdown height, and for optical backscatter sensors (OBS) 1, the relationship shows the best agreement
The investigation of the ship-induced waves and the associated sediment suspension were conducted based on the field measurements results

Summary

Introduction

Their morphological parameters will be adjusted under the constant incoming water flow and sediment, and eventually reach a dynamic or quasi-equilibrium state by altering the water flow, entraining and redepositing riverbed materials [1]. As the shipping traffic demands increase, the heavy shipping traffic puts much pressure on the hydrodynamic conditions and fluvial environment, by producing waves and associated currents, especially for the semi-enclosed or narrow waterways. E.g., estuaries or lagoons confined by tidal flats and marshlands, inland waterways, the key parameter depth Froude number is usually less than 1 due to the limited ship speed. This leads to the Kelvin wake wave being very small [2,15]. When the bottom shear stress exceeds a critical threshold value, sediment entrainment, resuspension and transport processes will occur [19]

Objectives

Methods

Results

Conclusion