A Study Of The Characteristics Of Flow And Deposition Of Turbidity Currents In Submarine High Sinuous Channels

Research on the flow and deposition of turbidity currents in submarine channels has been one of the hot topics due to its close relation with oil and gas resources. At present field surveys and lab experiments of turbidity currents have certain difficulties and insufficiency, three-dimensional numerical simulation is becoming more and more important in turbidity current research. It is presented here a three-dimensional numerical study of turbidity currents within a trapezoidal channel with high sinuosity(1.32, 1.56, 1.82) and streamwise slop 0.069° based on Reynolds-averaged Navier-Stokes equations, the buoyancy modified k-ε turbulence model and the orthogonalization of structured grid. The following characteristics concerning the flow, sedimentation of turbidity currents in high sinuous channels are found:(1) strong entrainment of ambient fluid, incline of isosurface of density at the bend apex increases with sinuosity;(2) the stripping flow at the outer bend apex flows into downstream channel resulting in more complex flow and deposition there;(3) river-like secondary flow is less pronounced at the bottom corner of outer channel bend apex compared with low sinuosity channels;(4) at bend apex cross section, erosion appears at the inner bank and bed deposits present a wavy tilt to the outer bank;(5) the longitudinal profile by the edge of channel bend apexes is more wavy than that for low sinuous channels, and the wave valley is positioned at the side of bend apex;(6) the longitudinal profile cutting through part of the channel shows that thicker channel bed deposit is intersected by arch-shaped thinner bank deposit and the profile dips more to the downstream. These characteristics revealed here may assists in inferring ancient environment and forecasting oil and gas resources in the deposition of turbidity currents based on turbidites observed today.