3-D numerical simulation of turbidity currents in submarine canyons off the Niger Delta

A three-dimensional unsteady numerical model is applied to simulate turbidity currents in deep submarine canyons located on the continental slope of the Niger Delta. In one of the few attempts to compare field core data to numerical simulations, we conduct several high resolution flow simulations wi...

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Bibliographic Details
Published in:Marine geology 2012-10, Vol.326-328, p.55-66
Main Authors: Abd El-Gawad, S.M., Pirmez, C., Cantelli, A., Minisini, D., Sylvester, Z., Imran, J.
Format: Article
Language:English
Subjects:
Brackish
Canyons
Computer simulation
deposition pattern
Grain size
Marine
Mathematical analysis
Mathematical models
Navier-Stokes equations
Niger Delta
numerical modeling
Sediments
submarine canyons
Turbidity
turbidity currents
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Summary:A three-dimensional unsteady numerical model is applied to simulate turbidity currents in deep submarine canyons located on the continental slope of the Niger Delta. In one of the few attempts to compare field core data to numerical simulations, we conduct several high resolution flow simulations with various boundary conditions to predict the grain size and deposition rates and compare the results to grain size and bed thickness from 22 piston cores collected at different elevations above the canyon thalweg. The model solves the Reynolds-averaged Navier–Stokes equations (RANS), the Mellor–Yamada turbulence closure equations, and the sediment conservation equations for different grain size classes. The bed evolution is modeled using the Exner equation of sediment conservation allowing adjustment of the numerical grid due to bed level changes caused by sediment entrainment/deposition during each time step. The simulated flow fields suggest that turbidity current dynamics is strongly controlled by the seafloor topography. Simulated mean bed thickness and grain size show trends where values of bed thickness and grain size are fining upwards with the elevation above the channel thalweg. ► 3D Numerical simulations of turbidity currents in submarine canyons were performed. ► Complex flow patterns are affected by the channel geometry and the local slope. ► Four grian-size classes were simulated and maps of deposition rate are presented. ► Grain-size and bed thickness variations with elevation above thalweg are presented. ► Comparison of numerical results show good agreement with data from 22 piston cores.
ISSN:0025-3227
1872-6151
DOI:10.1016/j.margeo.2012.06.003