伶仃洋水动力环境分析及治理策略探讨

珠江口伶仃洋四口门是珠江三角洲主要的泄洪纳潮通道，其水动力环境的变化是伶仃洋冲淤演变最直接原因，而伶仃洋的冲淤演变会关系到伶仃洋口门泄洪纳潮的能力，关系到珠江三角洲的防洪、排涝和经济发展等，根据实测资料及已有的研究成果，分析伶仃洋周边环境的变化原因，从河口地形的冲淤演变分析伶仃洋周边环境及其水动力环境的改变，并探讨伶仃洋河口整治策略。认为应采取输沙导流措施，减少淤积，保证口门通畅，保持伶仃洋潮流动力。  

河口滩涂围垦对水动力环境影响研究综述

通过综述评价，认为河口滩涂利用对水动力环境的影响主要体现在:滩涂围垦使得工程水域的水动力环境发生改变，迫使原有的河床稳定状态重新调整；大量的泥沙淤积导致陆域向海发展，海岸发生改变，导致潮滩失去对潮能的存储与耗散作用，改变潮汐范围；大规模的围垦也会使河口缩窄，破坏滩涂的湿地形态，导致河流的行洪能力可能降低，使周边城镇易受洪涝灾害。提出应将滩涂利用对水动力、河口岸线变化和防洪御潮等方面的影响进行系统评价，以指导滩涂的高效利用与保护。  

长兴岛围涂造地水动力环境响应数值模拟

长兴岛实施滩涂圈围工程对周边水动力环境具有一定的影响。为了研究其波及范围和影响程度,根据大量的现场监测资料,建立了长江口二维水动力模型,分别对围涂造地工程实施前后的潮流场进行数值模拟。分析表明:围涂造地对长江口的影响区域主要集中在围堤工程区东侧横沙通道下游、工程区南侧长兴南岸水道下游等局部水域内,对距离较远的水域基本没有影响,整体河势受影响程度较小。  

深中通道工程对珠江口水动力环境影响

深圳至中山跨江通道工程(简称深中通道)连接深圳和中山两市,跨越珠江口内伶仃洋"三滩两槽",大型人工岛及大量桥墩的存在必然对珠江口水域的水流动力环境造成一定的影响。通过伶仃洋潮流物理模型试验,研究深中通道各工程方案对珠江口水动力环境的影响。研究结果表明:A2方案(伶仃航道隧道+矾石航道桥梁)对潮位影响最大、其他次之;人工岛及桥墩附近水域流态变化较明显,以人工岛最大,通风井、锚碇、主塔、索塔等建筑物次之,非通航桥墩附近流态变化不明显,桥轴线5 km以远水域已基本不受工程影响。总体而言,各工程方案对伶仃洋滩槽格局影响都不大,结合其他专题研究,一致推荐A3方案(伶仃航道桥梁+矾石航道隧道)作为深中通道合理可行方案。  

Simplified hydrodynamic models for the analysis of marine propellers in a wake-field

This paper presents a comparison among different hydrodynamic models for the analysis of the unsteady loads delivered by a marine propeller working in an axial, non-uniform inflow. Specifically, for a propeller subjected to a wake-field dominated by local high-frequency changes in space, the unsteady hydroloads predicted by the Nakatake formulation are compared with those given by the Theodorsen and Sears theories, respectively. Drawbacks and potentialities of these approaches are highlighted to assess a computationally efficient hydrodynamic solver for the analysis of operating conditions where propeller blades are significantly perturbed by a multi-harmonic onset-flow. Guidelines coming from this investigation may drive the choice of a fast and reliable unsteady propeller modeling that represents a good trade-off between accuracy of simulation and cost of computation within implementation in Computational Fluid Dynamics （CFD） solvers. The hydrodynamic formulations herein proposed are validated through numerical comparisons with the （accurate but computationally expensive） propeller loads predicted by a fully 3-D panel-method Boundary Element Method （BEM） solver, suited for the analysis of propellers operating in a complex hydrodynamic environment.