PRECISE WATER VELOCITY MEASUREMENTS USING PHOTOGRAMMETRIC TECHNIQUES1

ABSTRACT Necessary input parameters for studying mixing zone characteristics of thermal plumes are horizontal surface and subsurface water velocities. Using time lapse aerial photography and analytical photogrammetric techniques, movements of drogues in an effluent plume were traced. From these traces accurate velocity vectors were obtained. Photographic coordinates of drogue images were measured using a glass scale. From the photo coordinates and the results of a ground control survey, an analytical solution was made for positions of drogues in the water at known intervals of time. Drogue positions were mapped for selected exposures thereby providing a visual display of velocity vectors in the study area. A rigorous error analysis was performed to determine the validity of the computed results.     

薄膜结构风致振动研究进展

薄膜结构具有质量轻、刚度小、自振频率低的特点 ,因而属于风敏感结构。作用在薄膜结构上的风荷载 ,除与气流本身的特性有关外 ,还与结构在风荷载作用下的位移、速度、加速度等有关 ,从而引起附加的气动力。因此 ,在研究薄膜结构的风致振动时 ,必须考虑流固耦合作用。笔者对薄膜结构的风振研究方法进行了总结 ,主要介绍了简化气弹力学模型方法及简化流体力学解析模型方法 ,并分别用于分析小于临界风速时结构的反应和确定结构的颤振临界风速。     

1983年山东菏泽5.9级地震地下流体前兆异常识别与检验性预测

对1983-11-07山东菏泽5.9级地震前地下流体前兆异常特征进行了识别与研究,分析了菏泽5.9级地震前地下流体前兆异常的阶段性、层次性和同步性特征,利用震前地下流体高频突变异常频次速率和异常频次累加值的变化,采用地下流体层次跟踪震情预测方法对菏泽5.9级地震长期、中期和短临三个时间尺度的震情进行了检验性预测。     

FIELD MEASUREMENT OF FLOW VELOCITIES,SUSPENDED SOLIDS CONCENTRATIONS,AND TEMPERATURES IN LAKE OKEECHOBEE1

ABSTRACT: This paper presents a field investigation of collecting hydrodynamic and sediment data in Lake Okeechobee with analyses examining mechanisms affecting sediment resuspension in the lake. Lake Okeechobee is a large subtropical lake located in south central Florida. Three‐dimensional flow velocities, suspended solids concentrations (SSC), and temperatures at four locations were measured from January 18 to March 5, 2000. Analyses of these data indicate that wind is the dominant factor in driving flow velocities and therefore transporting suspended solids. Wind direction also affects the SSC, especially in the north central and west littoral areas of the lake. The surface and bottom velocity components frequently flow in opposite directions, forming a stratification of the water column and preventing suspended solids from settling out. This retention of SSC in the water column may have a strong impact on the water quality of Lake Okeechobee. This study provides valuable storm event data and mechanism analyses, which will improve our understanding of the transport of suspended solids, thermal exchanges, and flow patterns within Lake Okeechobee.     

敏感性分析在燃烧毒物和自由基生成机理研究中的作用

针对燃料氧化的详细/半详细化学反应动力学机理，采用定量研究模型与出现在模型中各种参量之间关系的系统化方法--敏感性分析法，研究各基元反应对燃料过程中毒物和自由基生成的影响系数随时间的变化关系，为反应设计提供理论指导。     

丹巴县邛山沟特大灾害性泥石流汇流过程分析

在实际调查的基础上,对2003年7月11日发生在四川省丹巴县邛山沟的特大灾害型泥石流汇流过程进行了模拟.研究发现,邛山沟泥石流的产生,系由于流域基岩表面的残破积物在70多天的断续降雨过程中饱和或接近饱和,在7月11日晚突降暴雨的作用下,沿途坡面土体基本同时启动,坡面泥石流汇流,产生高容重的粘性泥石流,最后与左支沟(甲沟)的洪水汇合形成大规模的泥石流.沿途由于粗大颗粒的堵塞,峰值流量在有些断面迅速增大.     

A STEPWISE PROCEDURE TO DESIGN PLUVIAL DRAINAGE SYSTEMS IN AGRICULTURAL ZONES1

ABSTRACT: This paper describes a procedure to design pluvial drainage systems in such a way as to prevent large excavation volumes and erosive velocities. To this end the storage capacity of the channel system is taken into account. In a preliminary step, the procedure employs an approximate method to determine the channel dimensions. Therefore, the dimensions are adjusted by means of a numerical method of solution of the unsteady flow equations. An example is included.     

KZNJ-1型高效口罩效率检测装置的研制

本文详细介绍了KZM-1型高效口罩效率检测装置的研制背景、检测原理和装置性能，实验研究结果表明：此检测装置的各项性能指标均达到国家标准GB19083和GB2626的要求。     

Enhancing Hyrdological Simulation Program – FORTRAN Model Channel Hydraulic Representation1

Abstract: The hydrological simulation program – FORTRAN (HSPF) is a comprehensive watershed model that employs depth‐area‐volume‐flow relationships known as the hydraulic function table (FTABLE) to represent the hydraulic characteristics of stream channel cross‐sections and reservoirs. An accurate FTABLE determination for a stream cross‐section site requires an accurate determination of mean flow depth, mean flow width, roughness coefficient, longitudinal bed slope, and length of stream reach. A method that uses regional regression equations to estimate mean flow depth, mean flow width, and roughness coefficient is presented herein. FTABLES generated by the proposed method (Alternative Method) and FTABLES generated by Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) were compared. As a result, the Alternative Method was judged to be an enhancement over the BASINS method. First, the Alternative Method employs a spatially variable roughness coefficient, whereas BASINS employs an arbitrarily selected spatially uniform roughness coefficient. Second, the Alternative Method uses mean flow width and mean flow depth estimated from regional regression equations whereas BASINS uses mean flow width and depth extracted from the National Hydrography Dataset (NHD). Third, the Alternative Method offers an option to use separate roughness coefficients for the in‐channel and floodplain sections of compound channels. Fourth, the Alternative Method has higher resolution in the sense that area, volume, and flow data are calculated at smaller depth intervals than the BASINS method. To test whether the Alternative Method enhances channel hydraulic representation over the BASINS method, comparisons of observed and simulated streamflow, flow velocity, and suspended sediment were made for four test watersheds. These comparisons revealed that the method used to estimate the FTABLE has little influence on hydrologic calibration, but greatly influences hydraulic and suspended sediment calibration. The hydrologic calibration results showed that observed versus simulated daily streamflow comparisons had Nash‐Sutcliffe efficiencies ranging from 0.50 to 0.61 and monthly comparisons had efficiencies ranging from 0.61 to 0.84. Comparisons of observed and simulated suspended sediments concentrations had model efficiencies ranging from 0.48 to 0.56 for the daily, and 0.28 to 0.70 for the monthly comparisons. The overall results of the hydrological, hydraulic, and suspended sediment concentration comparisons show that the Alternative Method yielded a relatively more accurate FTABLE than the BASINS method. This study concludes that hydraulic calibration enhances suspended sediment simulation performance, but even greater improvement in suspended sediment calibration can be achieved when hydrological simulation performance is improved. Any improvements in hydrological simulation performance are subject to improvements in the temporal and spatial representation of the precipitation data.