Wave-current impacts on surface-piercing structure based on a fully nonlinear numerical tank

Fully nonlinear wave-body interactions for a surface-piercing structure with combined wave-current flow in different water depths are studied by using a 2-D numerical tank. The model is based on Reynolds averaged Navier-Stokes(RANS) equations and renormalization group(RNG) k- model. The mean and maximum wave-current impacts, including forces in two directions and rotational moment, are calculated and discussed. The effects of U/ C and water depth condition on forces and moment have been investigated and the results for combined irregular waves and currents are compared with those induced by combined regular waves and currents.     

Analysis of silt behavior induced by water waves

Based on the weak non-elastic porous model, the expressions of pore pressure, effective stress and displacements of soil skeletal frame and pore water have been deduced for a finite depth seabed. The distributions of several physical parameters have been analyzed for three kinds of marine sediment, including pore pressure, effective stress, stress angle, displacement of skeletal frame and pore fluid, and the variations of elastic waves with wave period. According to the experimental results, the resonant phenomena in the silt bed and the mechanism underlying such events have been discussed. It is proposed that the existence of a stiff soil layer inside the silt bed is a necessary condition for resonance to occur, and the possible location of resonance can be forecasted.     

反相微乳液法制备纳米氧化铁颗粒的结构及性能

测定了多种表面活性剂构成的反相微乳液体系对于水及盐溶液的载量,找到了一种具有较高氯化铁溶液载量的反相微乳液体系Egepalco-520/环己烷(或石油醚PE)/H2O.利用该体系制备纳米氧化铁的粒径与形态和盐溶液的浓度、加入量及表面活性剂/油的比有关.在表面活性剂/油比较高时,可以制备出粒径小于10 nm的氧化铁,但所制备的氧化体的结晶性较差.     

波浪作用下悬移质泥沙运动的两相流数值模型

该文采用基于水沙两相紊流的数值模型对波浪作用下的悬移质泥沙运动进行研究。基本方程中将水相和颗粒相通过相间作用力进行耦合,合理地考虑了相间相对运动的影响。数值计算方法为有限体积法,对流项处理利用了三阶精度的QUICK格式,离散方程组求解采用的是TDMA迭代方法。计算得到的悬移质泥沙垂线时均计算值与不同尺度的水槽实验数据吻合很好,表明数学模型及其计算方法对于低浓度水沙两相问题是合理的。该研究还探讨了悬沙浓度、泥沙沉降速度以及各种相间作用力随时间的分布规律。     

致密储层中石油充注特征的在线显微成像研究

致密储层岩石渗透率低，储集空间受其微纳米级孔隙控制，毛管力作用显著增强。认识油气的微观充注特征是分析运聚成藏的基础。利用自研的岩心流体驱替在线三维显微成像系统，开展致密储层样品油充注过程观测，提出样品整体和孔隙两级的含油特征综合定量分析方法。以相同流程的驱替在线核磁共振测试为对照，揭示不同时刻在线二维直接数字化摄影(Digital Radiography, DR)的平均差值，可用于评价样品整体含油量变化；基于高精度孔隙网络抽提的孔隙级流体饱和度计算方法，实现了图像可分辨的孔隙与孔喉油充注程度的定量评价。通过多层次数据、不同方法的组合，可满足不同研究对动态特征捕捉、孔隙分辨能力及成像视野等差异化需要。分析结果表明，鄂尔多斯盆地不同致密储层两块岩石样品的含油饱和度随注油量的增加，均呈现开始上升较快、后期减缓的特点；相同注入流速下，相对高渗样品油充注初期含油饱和度上升速度更快，最终含油饱和度较高；随着注油量的增加，较高渗样品的大孔隙含油饱和度持续增加，低渗样品大孔隙的含油饱和度呈U形变化，表现出油、水反复占据孔隙的特点。