PREDICTION OF MAXIMUM SCOUR DEPTH AROUND LARGE-DIAMETER CYLINDER UNDER THE EFFECTS OF BOTH WAVE AND CURRENT

1.　INTRODUCTIONDue to the effects of both wave and current a round the isolated offshore large dimensional struc ture(D/L ≥ 0.20), the serious partial scour willresult in the destruction of its foundation. As apractical engineering problem, local scour aroundthe large sized structure has already drawn muchattention, but most of the researches concentrateto scour problem only with wave or only with cur rent[1 3]. There have been very few researches onthe partial…     

人工神经网络在水资源管理中的应用

近几年来，人工神经网络受到越来越多从事水资源研究学者的关注，成为该领域的新理论。文中的目的是想对人工神经网络在水资源管理领域的应用进行一个总结。这些应用包括特征辨识、预测与预报、函数逼近、优化计算等多个方面。文中首先对研究情况进行了一般性的回顾，然后分别对各类应用重点进行了评述，最后通过总结给出了进一步研究的建议。     

长距离输水系统的神经网络模型研究

常规特征线算法在仿真模拟长距离有压输水系统流量调节过渡过程时，存在计算时间较长等不足，故无法很好地满足实时控制和优化调度的需要．本文利用人工神经网络(ANN)所具有的高度非线性全局作用、良好的自适应性及联想记忆功能等优点，将人工神经网络引入到过渡过程的分析中，建立合适的神经网络模型，并通过该模型得出一系列计算成果．该成果与传统算法所得的结果相比较表明，人工神经网络在过渡流的分析中是可行的，并具有明显的优势．     

IDENTIFICATION OF GAS-LIQUID FLOW REGIMES IN A HORIZONTAL FLOW USING NEURAL NETWORK

The knowledge of flow regimes is very important in the study of a two-phase flow system. A new flow regime identification method hased on a Probability Density Function (PDF) and a neural network is proposed in this paper. The instantaneous differential pressure signals of a horizontal flow were acquired with a differential pressure sensor.The characters of differential pressure signals for different flow regimes are analyzed with the PDF. Then, four charaeteristic parameters of the PDF curves are defined, the peak number (K1), the maximum peak value (K2), the peak position (K3) and the PDF variance (K4 ). The characteristic vectors which consist of the four characteristic parameters as the input vectors train the neural network to classify the flow regimes. Experimental results show that this novel method for identifying air water two-phase flow regimes has the advantages with a high accuracy and a fast response. The results clearly demonstrate that this new method could provide an accurate identification of flow regimes.     

用动态网络规划法制定水电厂开停机计划

制定水电厂开停机计划是厂内经济运行的一个重要方面。文中就具体的应用对象，以整个时段内耗水量最小为准则，使用动态网络规划法制定了水电厂日运行计划，并给出了计算结果;同时，将该算法与常用的动态规划法进行了比较。     

NUMERICAL MODELING FOR POSITIVE AND INVERSE PROBLEMS OF 3-D SEEPAGE IN DOUBLE FRACTURED MEDIA

Three-dimensional seepage in double fractured media was modeled in this paper. The determination of hydraulic conductivity tensor of rock mass is a vital problem for the sea water intrusion or sea water encroachment and seepage of fissured medium. According to the geological and hydrogeological conditions for the Three Gorges Project (TGP),2nd stage construction of the Three Gorges Project(TGP),the physical and mathematical models for the groundwater movement through the 3D double fractured media of rock mass during construction were established in this paper. Based on discontinuity control inverse theory, some related parameters of double fractured media were inversed with flux being the known quantity and calibration of water table the objective function. Synchronously, the seepage field of the construction region was systematically analyzed and simulated, the results of which exhibit that the double fractured media model of fracture water can comprehensively and correctly describe the geological and hydrogeological conditions in the construction region.