沉积学报2025，Vol.43Issue(3)：912-938,27.DOI:10.14027/j.issn.1000-0550.2024.093
浊流对多段平行褶皱响应的二维数值模拟
Two-dimensional Numerical Simulation of Turbidity Current Responses to Multi-segment Folds
摘要
Abstract
[Objective]Continental margins often develop fold and thrust belts,which have a major control over deep-water deposition processes,such as turbidity currents.These structures play a crucial role in shaping the sea-floor and influencing sediment transport and deposition patterns.However,due to the difficulties in obtaining rele-vant geological data and conducting field measurements of turbidity currents,quantitative research on the hydraulic and depositional responses of turbidity currents to multi-segment folds is largely understudied.[Methods]In this study,computational fluid dynamics(CFD)and the finite volume method(FVM)were used to conduct a two-dimensional numerical simulation study on the hydraulic and depositional responses of turbidity currents to multi-segment parallel folds.Using the Flow-3D software and the Reynolds-Averaged Navier-Stokes(RANS)equations,six simulation experiments were designed by systematically varying fold morphology parameters(width,height,and spacing)and initial turbidity flow velocity.These parameters are based on in situ observations and physical flume experiments to ensure realistic input conditions.[Results and Conclusions](1)under the influence of multi-segment parallel folds,reverse flows develop at the bottom of the turbidity current,including upstream-propagating reverse underflows generated by the blockage of the folds and downstream-propagating reverse under waves arising from perturbations after the turbidity current flows over the folds.(2)The propagation distance,velocity,and scale of the underflow reflect the extent to which the turbidity current is disturbed by the folds.By comparing the reverse flows,the turbidity current is shown to experience more severe disturbances at the back row folds than at the front row folds.This suggests that the spatial arrangement of the folds plays a critical role in modulating the flow dynamics and sedimentation patterns of turbidity currents.(3)The depocenters of turbidity currents on folded morphologies are pri-marily distributed on the upstream-facing slopes and in front of the folds,forming overlapping strata and gradually fining upstream.The deposition of turbidity currents is controlled both by the morphology of the folds and the hydrau-lic conditions of the turbidity current.Higher folds and slower flow velocities of the turbidity current promotes more deposition,indicating a strong coupling between the physical characteristics of the folds and the flow properties of the turbidity currents.Additionally,the front row folds accumulate more sediment than the back row folds,highlighting the influence of fold positioning on sediment dispersal.(4)The disturbance of the turbidity current by the front row folds and the separation distance between the two folds affect the hydraulic characteristics and depositional processes of the turbidity current flowing through the back row folds.When the turbidity current is disturbed by the front row folds and the separation distance between two folds is sufficiently small to maintain its perturbed state,the current is more likely to flow over the back row folds,further reducing the total amount of sediment deposited on the upstream-facing slope of the back row folds.The main findings of this study are consistent with those of previous studies focusing on natural examples.Therefore,this study helps to reveal the hydraulic and depositional patterns of turbidity currents occurring in multi-segment folds and provides a reference for oil and gas exploration in related regions.关键词
深水褶皱带/浊流/数值模拟/逆向流/浊积系统Key words
deepwater fold belt/turbidity current/numerical simulation/reverse flow/turbidite system分类
天文与地球科学引用本文复制引用
卢心炜,葛智渊,许鸿翔,王俊辉,李晋,李威,樊依霖,张春明..浊流对多段平行褶皱响应的二维数值模拟[J].沉积学报,2025,43(3):912-938,27.基金项目
国家自然科学基金项目(42102119,42302185)[National Natural Science Foundation of China,No.42102119,42302185] （42102119,42302185）
