挟沙水流紊动通量的实验研究

利用MicroADV的声强衰减与泥沙浓度的关系,提供一种无接触测量含沙量浓度的方法;同时根据连续采样得到脉动的泥沙浓度,对这种脉动浓度进行了初步分析并根据得到脉动浓度,初步定量地研究了紊动扩散通量大小及其平衡关系.     

海岸动力环境下射流运动研究综述

开展海岸动力环境下射流运动规律和扩散机理研究,对于丰富复杂动力条件下的射流基本理论、指导沿海地区污水有序向海排放有着重要的理论和现实意义。系统回顾和总结了国内外在这一领域的研究内容和相关研究成果,评述了潮流(水流)、波浪和波流环境下射流运动规律的研究进展,指出了进一步开展波流相互作用下射流运动研究的可行性和必要性,并提出了利用物理实验和大涡数值模拟手段对波流共同作用下射流特性进行综合研究的思路和方法。     

油井射流排砂泵扩散管出口流场分析

依据RNG-ε双方程湍流模型,建立油井射流排砂泵固液两相流方程;在此基础上,应用CFD计算机分析软件,对比分析了扩散管出口突变结构和渐变结构的射流排砂泵的效率、固相比、速度场分布、压力场分布。数值分析结果表明：射流泵扩散管出口采用渐变结构,可以有效减少固液两相流的逆向速度矢量,是提高射流排砂泵综合性能的有效手段。     

深圳市污水排海放流管注浆加固工程实例

针对深圳市污水排水放流钢顶管已施工部分,因顶管施工过程中周围土体位移严重,局部出现过塌方,造成部分土体流失,引起钢顶管扭曲变形。因自然环境恶劣,地质条件复杂,为减缓或控制不均匀变形的进一步发展,对不同地段分别采用劈裂注浆和渗透注浆加固顶管周边土体处理方案,达到设计要求。     

地下污水管道泄漏对环境影响研究进展

地下污水管道的泄漏普遍存在.污水管道一旦泄漏,将会对土壤、地下水环境产生严重的影响.主要阐述了管道泄露的研究现状以及地下水入渗对地下水管的危害;总结了地下水管网泄露的种种原因;分析了污水管道泄露对地下环境的各种影响,主要表现为:改变土壤的理化性质,引起土壤污染,造成土壤富营养化,进而导致地下水污染,减少淡水资源,引起水土流失.     

污水侧排近区特性的三维数值模拟研究

给出描述热污水全深度侧排的三维湍流数学模型，并考虑了浮力效应。进而采用Chu的实验资料进行检验，计算结果和试验资料的吻合证明了模型和方法的正确性，为进一步数值预报其近区特性奠定基础。     

三元复合驱采出污水回注渗透率的影响因素分析

基于大庆油田三元复合驱采出污水回注对地层存在的损害现象,研究了污水回注渗透率的影响因素。采用室内水驱实验方法,对三元复合驱采出污水中悬浮物、油、碱、聚合物等因素进行了分析,阐述了各种成分对渗透率的影响机理。结果表明,悬浮物颗粒会堵塞孔隙喉道,油产生的“贾敏效应”将增大油水流动阻力,碱与岩石及黏土矿物问的物理化学作用会使地层结垢,聚合物在岩芯中的吸附和滞留共同造成地层渗透率的下降。因此,建议将三元复合驱采出污水中悬浮物、油、碱、聚合物等处理合格后再进行回注,以减轻对地层的损害。     

污水侧排近区特性的三维数值模拟研究——数学模型及其检验(Ⅰ)

给出描述热污水全深度侧排的三维湍流数学模型,并考虑了浮力效应.进而采用Chu的实验资料进行检验,计算结果和试验资料的吻合证明了模型和方法的正确性,为进一步数值预报其近区特性奠定基础.     

污水侧排近区特性的三维数值模拟研究——近区特性的数值预报(Ⅱ)

探讨了弗劳德数对近区流动特性的影响,在此基础上,给出了岸边全深度热排放的浮力射流发生吸附的临界条件.     

用VOF方法模拟静止浅水环境中的垂向紊动射流

以k-ε紊流模型为基础,针对浅水环境垂向射流的水面会有明显突起情况,采用VOF(Volume of Fluid)方法追踪自由面,建立了适合浅水环境垂向平面紊动射流的二维数学模型.对不同入射速度、水深、入射口宽度组合进行了大量的数值模拟实验,对整个流场的分布作了分析,发现自由面的分布特点和速度矢量场的分布特点相对应;中轴线附近的自由面隆起具有自相似性,文中给出了拟合表达式;由于水面的阻滞,中轴线上垂向速度的衰减较自由射流快,衰减规律随水深和射流宽度而异.     

Tsunamis from submarine landslides

Most tsunamis are generated by earthquakes, with secondary, less frequent, mechanisms including subaerial and submarine landslides, volcanic eruptions and (extra‐terrestrial) bolide impacts. Different mechanisms generate tsunamis with different magnitudes, travel distances and impacts. Submarine landslides had been mapped and studied for decades but records suggested that only a few had generated tsunamis, and that these were minor. It was not until 1998, when a slump on the seabed offshore of northern Papua New Guinea caused a tsunami wave up to 15 m high that killed over 2200 people, was the significance of submarine landslides in tsunami generation realised. A combination of new (multibeam) seabed mapping technology and the development of improved numerical tsunami models for tsunami generation led to the recognition of the landslide tsunami mechanism of the PNG event. As a result the hazard from submarine landslides in tsunami generation is now recognized and better understood. Extensive mapping of ocean margins reveals that submarine landslides are common. Although many of these probably generated tsunamis, few have been identified, so their hazard remains uncertain. This article describes how the hazard from submarine landslide tsunamis was first recognized, how submarine landslides generate tsunamis, why they were previously discounted as a major hazard, and their potential hazards. An important aspect of the recognition of the tsunami hazard from submarine landslides has been the significance of geology, which has contributed to a subject previously dominated by seismologists.     

Transitional submarine fan deposits from the late Precambrian Kongsfjord Formats submarine fan, NE Finnmark, N. Norway

ABSTRACT Three transitional submarine fan environments are recognized in the late Precambrian, 3-2 km thick Kongsfjord Formation in NE Finnmark, North Norway, namely: (1) middle to outer fan; (2) fan lateral margin, and (3) fan to upper basin-slope deposits. Middle to outer fan deposits have a high proportion of sandstones, typically showing Bouma T _bede with T _a in the thicker beds. Deposition was mainly from sheet flows with rare shallow channels. Middle to outer fan deposits are an association of sandstone packets less than 10 m thick but commonly only a few metres thick, interpreted as channels or lobes. Interchannel and fan fringe deposits occur as discrete packets of beds between the thicker bedded and coarser grained channel or lobe deposits. Fan lateral margin deposits are recognized on the basis of their stratigraphic position adjacent to inner/middle fan deposits. They are characterized by: (a) a relatively high proportion of fine-grained sandstone/siltstone turbidites compared to other major fan environments; (b) relatively small channels oriented at various angles to the regional basin slope; (c) lobes associated with channels, and (d) abundant clastic dykes and other soft-sediment deformation. Fan lateral margin deposits are distinguished from the outer fan/basin plain successions on account of the very high proportion of siltstone turbidites comparable with middle fan inter-channel deposits. Fan to upper basin-slope deposits occur at the top of the formation as an alternation of sandstone turbidites, most of which are laterally discontinuous, and very thin-bedded upper basin-slope siltstones with slide deposits.     

Downward development of overgrowths from echinoderm fragments in a submarine environment

Fragments of echinoderms in the Karaisali Limestone (Miocene) of the Adana Basin, Turkey, show large syntaxial overgrowths which are restricted mostly to their undersides, whilst the upper surfaces are covered by micrite. Although this pendant style of the overgrowths is reminiscent of vadose zone ‘gravitational cement', they appear to have formed in the open voids of sediments in the marine environment, simultaneously with, as well as after, the internal deposition of micrite.     

Chlorine in submarine volcanic glasses from the eastern manus basin

Submarine volcanic glasses from the eastern Manus Basin of Papua New Guinea, ranging from basalt to rhyodacite, clarify the geochemical behavior of Cl in arc-type magmas. For the Manus samples, Cl is well correlated with non-volatile highly incompatible trace elements, suggesting it was not highly volatile and discounting significant seawater contamination. The Cl partition coefficient is close to but slightly lower than that of Nb and K₂O, a behavior similar to that in mid-ocean ridge basalts (MORB) and ocean island basalts (OIB). The similar incompatibilities of Cl and Nb imply that the Cl/Nb values of the eastern Manus Basin glasses reflect their magma source. For glasses from other west Pacific back-arc basins, Cl/Nb, Ba/Nb, and U/Nb increase towards the subduction trench, indicating increased contribution of a component enriched in Cl, Ba, and U, likely from subduction-released slab fluids. It is estimate that ∼80% of the Cl in the Manus arc-type glasses was added directly from subducted slab-derived fluids. We have also modeled Cl behavior during magma evolution in general. Our results show that the behavior of Cl in magma is strongly influenced by pressure, initial H₂O content, and the degree of magmatic fractionation. At early stages of magmatic evolution, for magmas with initial H₂O content of <4.0 wt%, Cl is highly incompatible under all pressures. By contrast, for more evolved magmas at moderately high pressure and high H₂O contents, considerable amounts of Cl can be extracted from the magma once H₂O saturation is reached. Accordingly, Cl is usually highly incompatible in MORB and OIB because of their low H₂O contents and relatively low degrees of fractional crystallization. The behavior of Cl in arc magmas is more complicated, ranging from highly incompatible to compatible depending on H₂O content and depth of magma chambers. The behavior of Cl in the eastern Manus Basin magmas is consistent with low H₂O contents (1.1-1.7 wt%) and evolution at low pressures (<0.1 GPa). Modeling results also indicate that Cl will behave differently in intrusive rocks compared to volcanic rocks because of the different pressures involved. This may have a strong influence on the mechanisms of ore genesis in these two tectonic settings.     

基于相似性的多沙水库坝址含沙量预测

坝址含沙量过程是合理进行水库水沙调度的重要依据.在浑水总流模型的基础上,提出了基于洪水相似性的多沙水库坝址含沙量预测方法.通过聚类分析将洪水案例分组,并分别率定模型参数;根据洪水相似性动态选择未知洪水模型参数;进行模型计算.结果表明,分组率定参数一定程度上能够提高坝址含沙量预测精度,尤其是沙峰出现时刻.这对指导水库水沙调度具有实际意义,有助于决策者制定合理的排沙时机,提高排沙效率.     

基于微分对策理论的多沙河流水库调度

水库的排沙问题一直是多沙河流水库调度研究的重点之一。由于大部分多沙河流的来水来沙主要集中于汛期,因此水库汛期的蓄水兴利与泄水排沙的矛盾十分突出,具有典型的博弈关系,该关系可以利用博弈的相关理论进行描述。基于微分对策理论,将多沙河流水库汛期的供水兴利与泄水排沙看作博弈的双方,建立起以排沙和供水的综合效益作为性能指标函数的多沙河流水库汛期调度模型,研究了多沙河流水库汛期的调度问题,并通过陕西黑河某水库的实测资料对该模型进行了验证计算。计算结果表明,建立的调度模型能够较好地反映多沙河流水库汛期调度中的主要矛盾,实现对供水与排沙综合效益的优化。     

高压水射流极小半径钻井技术研究现状与展望

高压水射流极小半径钻井技术是实现油气资源低成本、高效开发的重要技术手段。根据国内外高压水射流极小半径钻井技术研究及应用情况,系统分析了锻铣扩孔型液压式、锻铣扩孔型射流反推式和套管开窗型3种极小半径钻井技术的装备组成、钻进原理、工艺过程和应用效果,归纳了不同技术的优缺点和适用性。从应用于煤层气开发的角度,倡导锻铣扩孔型射流反推式极小半径钻井技术应作为一个进一步研究的方向,并提出了此技术在煤层钻进及转向过程中面临的难点问题和解决思路。针对极小半径钻井技术装备在地层适用性、钻进效率、增产效果等方面的瓶颈问题和新形势下能源开发对钻井技术装备的发展需求,建议应尽早开展煤层气井极小半径钻井复合增产技术、极小半径钻井提速增效技术、极小半径钻井-下筛管一体化钻完井技术以及自动化、信息化、智能化极小半径钻井技术的研究和工程试验。