Open AccessA numerical study of tidal bores
Author(s) -
Nining Sari Ningsih,
N. L. Siddiq,
Ayi Tarya
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1245/1/012059
Subject(s) - froude number , geology , mechanics , flow (mathematics) , surge , amplitude , water level , channel (broadcasting) , estuary , hydrology (agriculture) , geotechnical engineering , meteorology , geomorphology , oceanography , engineering , physics , geography , optics , cartography , electrical engineering
A tidal bore is a natural phenomenon forming a positive surge upstream and it has a remarkable effect on estuary zones and river ecologies. The tidal bore formation controlled by channel properties, tidal characteristics, and river discharge remains a research challenge. In this study, a tidal bore formation and its hydrodynamics characteristics have been numerically investigated by using a two-dimensional version of OpenFOAM (Open Source Field Operation and Manipulation) model to obtain a better understanding of the effects of flow velocity before arrival of the bore ( V 1 ), initial water depth ( d 1 ), and Froude number ( Fr ) on the propagation of the tidal bore. The numerical simulation results have confirmed earlier findings obtained under both field and laboratory data in which types of the tidal bores depend on the Froude number. An undular tidal bore occurs when 1 ≤ Fr < 1.25, while partially breaking undular bore appears for 1.25 ≤ Fr < 1.5 – 1.6. Further simulation results have revealed that the flow velocity before the bore passage (downstream flow or V 1 ) is more dominant than the initial water depth in affecting the Froude number. Meanwhile, the bore celerity ( U b ) is more affected by the initial water depth compared to the flow velocity before the bore arrival. It is found that the Froude number does not directly affect wave parameters of the bore, such as amplitude, length, period, and steepness of the wave. However, the wave length and period are directly proportional to the initial water depth, whereas the wave amplitude and steepness are associated with the velocity prior to the bore passage.