Scale Effect on Flow and Deposit of Sustained Turbidity Currents

Jasim Imran¹, Carlos Pirmez², and Heqing Huang^1
1 University of South Carolina, Columbia, SC
² Shell International E&P, Inc, Houston, TX

A numerical model of turbidity current has been developed. In this model, the Reynolds-averaged conservation equations of momentum, and mass of fluid and particle phases are solved using a finite volume method. The turbulence closure is obtained using the buoyancy modified k-epsilonƒnmodel. The interaction between the current and the erodible bottom boundary is simulated by solving the Exner equation of sediment conservation. The numerical grid is adjusted during the computation to account for changes in the bed level. The model is applied at different scales with domain lengths ranging from few meters to several kilometers. Different initial bed topography as well as flow conditions are considered. A densimetric Froude scaling is used in selecting the flow parameters at different scales. The effects of several relevant non-dimensional groups on the simulated flow field are analyzed. The simulation shows that there are important similarities and differences in the flow structure and sedimentation pattern at different scales. While some flow parameters show a reasonable similarity at different scales, others do not. This may have important implication on how laboratory results are upscaled and interpreted.