--> ABSTRACT: Numerical Modeling of Turbidity Current and Sedimentation in Meandering Submarine Channels, by Himangshu Das, Jasim Imran, Carlos Pirmez, and David Mohrig; #90906(2001)
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Himangshu Das1, Jasim Imran1, Carlos Pirmez2, David Mohrig2

(1) University of South Carolina, Columbia, SC
(2) ExxonMobil Upstream Research Co, Houston, TX

ABSTRACT: Numerical Modeling of Turbidity Current and Sedimentation in Meandering Submarine Channels

A numerical model of channelized Previous Hit2-DNext Hit turbidity current is developed and applied to study flow and in-channel sedimentation in submarine channels. Previous HitDepthNext Hit-averaged conservation equations of fluid mass and momentum, suspended sediment concentration, and turbulent kinetic energy expressed in a cylindrical-polar coordinate system are solved by a predictor-corrector explicit finite difference scheme. The model is capable of dealing with arbitrary planform and versatile boundary conditions, e.g., constant or surge type inflow, and multiple grain sizes of suspended sediments. Numerical experiments are conducted with various inflow conditions and different channel planforms to characterize the nature of in-channel deposition and erosion as well as tendency for meander Previous HitmigrationTop. Model runs made with erosional and depositional currents show some sharp contrast in cross-channel bed characteristics even though in both cases, the higher velocity is observed near the outside banks. Such contrast is also observed in seismic records of buried submarine channels. The model predicts an overall decrease in current velocity and suspended sediment concentration in the down channel direction and the channel strives for momentum to keep the sediments in suspension. It is necessity to have fractions of clay in the inflow to maintain momentum in the channel. Insignificant cross slope development is observed in all numerical experiments. This is due to the exclusion of bedload transport and secondary circulation from the model. Some numerical runs made with multiple grain-size classes have shown sediment sorting in the along channel and cross channel directions.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado