高压水射流计算机模拟可视化初探

在分析射流参数解析解的基础上,结合前人提出的有关经验公式,利用可视化软件工具和可视化图形工具,对高压水射流的射流结构和射流参数进行可视化模拟。阐明了模拟可视化的必要性和可行性,提出了可视化模拟在高压水射流技术研究上的几个可能的发展方向。     

ALTERNATIVE FUTURES USING THE WOLLMAN-BONEM MODELS1

Alternative futures are defined to be mutually consistent alternative combinations of assumed sets of future conditions. Alternative futures are employed in conjunction with the Wollman-Bonem model to project future water use. The model solutions under different alternative futures provide an indication of the direction and relative magnitude of changes in water use, both in quantity and quality, that may result from changes in policy-influenced variables, technology, and other data. The Wollman-Bonem model is employed in this paper as a tool to illustrate the alternative futures concept. The model can best be cast as an economic model. The model solutions are not given as a set of formal projections, but as various possible water-use-over-time curves. This should aid in disspelling the erroneous idea that it is possible to make distant projections of water use as a single curve. Multiple curves suggest that water use is really a function of many variables.     

ADMINISTRATION OF GROUND WATER AS BOTH A RENEWABLE AND NONRENEWABLE RESOURCE1

ABSTRACT: Ground water is intended to be administered in many western states as a flow or renewable resource. In Idaho, this administration is based on the appropriation doctrine of water rights. Two generalizations may be made concerning ground water. First, water artificially discharged from an aquifer system must deplete the total resource by that amount; water consumptively pumped from a well must be derived from either increased recharge, decreased discharge or a decrease of water in storage. Second, the annual rate of recharge to a ground-water system is often only a small percentage of the total resource in storage. Ground water may be divided into flow and stock portions. In those basins where the second generalization is true, most ground water may be classified as stock. However, only the flow portion of ground water may be developed if utilization of the resource is to be enjoyed over an infinite period. Data from the Raft River Basin in Idaho indicate that the flow and stock characteristics of ground water are time dependent. The resource exhibits the characteristics of both a renewable and nonrenewable resource. As a result, present administrative techniques do not provide for effective management of the resource.     

REGIONAL WATER QUALITY MANAGEMENT BY THE GENERALIZED REDUCED GRADIENT METHOD1

ABSTRACT: A river basin-wide water quality management system is considered. The river receives thermal as well as organic wastes. At-source treatment of these pollutants is imposed to control the basin-wide water quality. The related water quality standards are: the minimum DO concentration, the maximum allowable BOD concentration, the maximum allowable stream temperature, and the allowable rise in stream temperature. The general dynamic mathematical model representing water quality in streams and the thermal effects on BOD and DO concentrations is presented. The model is highly nonlinear in nature. The optimal management problem involving the model is solved by a recently developed nonlinear propgramming technique - the generalized reduced gradient (GRG) method. Comparison of results obtained by the GRG method vs. dynamic programming, and of results using a more realistic mathematical model vs. a simple model are presented. The analysis procedure can be applied to designing new and examining existing water quality programs, and to study the influence of alternate policies and constraints.     

A SYSTEMS STUDY OF STORM RUNOFF PROBLEMS IN A NEW TOWN1

A system study was conducted on the use of a large number of small reservoirs dispersed throughout an urban community as a means of storm water pollution control. The study was based on an area within the “new city” of Columbia, Maryland. Water collected and stored in the reservoirs is treated for release or use in meeting sub-potable and potable water demands in the community. Design and performance criteria were developed for such a system. A simulation model and a computerized evaluation technique were used to select the optimal locations and system configurations. The results of this study indicated that such a system would be less expensive than a conventional engineering approach to storm water pollution control. Further, the benefits derived from use of the storm water as a water supply can offset a portion of the cost of pollution control. Several secondary benefits also result from this concept including erosion and sediment control, storm flow dampening, and recreational facilities. A program is now underway to demonstrate this concept in Columbia, Maryland.     

COMPREHENSIVE INFORMATION RETRIEVAL IN THE FIELD OF WATER RESOURCES1

The ages-old and ever-growing need for communication and information retrieval among scientists has found expression in the development of indexes, abstracts, reviews and combinations or variations of such. A short review of such efforts is followed by a discussion of efforts along these lines in the new field of water resources science and technology. Such undertakings as the Information Retrieval System of the American Society of Civil Engineers and of the U.S. Water Resources Research Office are compared with that of the American Water Resources Association.     

煤气设备水封的有效高度

通过分析煤气设备水封的有效高度的有关规定,及水封有效高度的计算方法,阐述生产单位水封跑气事故情况,提出了煤气设备水封的有效高度的新计算方法。     

关于城市水“分流”的设想

淡水是人类赖以生存的资源,淡水的短缺已成为制约经济发展的重要因素之一,并危及人类的生存。解决淡水危机,加强淡水资源利用和管理已刻不容缓。对城市进行分流供水,对产生的废水进行分流回收处理,是实现淡水资源的持续利用,满足城市用水需要的新思路     

The use of terrestrial ecoregions as a regional-scale screen for selecting representative reference sites for water quality monitoring

A process has been developed to select watersheds that are representative of terrestrial ecoregions and that are relatively undisturbed by human activity. Using an existing land classification system at two hierarchical levels of resolution, representative subsets (ecodistricts) of large-scale ecoregions were selected, on the basis of their physiographic, biological, and climatological attributes, to represent the ecoregions. This was achieved using a frequency distribution analysis of existing attribute data and choosing the ecodistrict most closely resembling the most common set of conditions for that ecoregion. Within each ecodistrict, river basins were selected through a best-judgement evaluation of land use, coupled with an assessment of the size and location of each river basin, in order to meet the condition of minimal human impact. Preliminary assessment of water quality data collected from six watersheds selected in this way suggests that the process is effective in targeting regional scale river basins exhibiting the desired characteristics.     

Method for determining minimum pool requirements to maintain and enhance salmonid fisheries in small Wyoming reservoirs

Methods for determination of minimum pool levels in reservoirs that consider sport fishery values are being sought by managers. We developed a technique for assessing the effects of incremental changes in minimum pool levels on potential salmonid abundance in small (<100 surface hectares at full pool) reservoirs in Wyoming managed for irrigation and municipal water supplies. The method has two components. One component is used to determine the minimum pool level needed to eliminate the risk of overwinter loss of salmonids due to low dissolved oxygen concentrations. The other component predicts the potential biomass of salmonids in reservoirs as a function of water depth and total dissolved solids concentration of the reservoir water. Application of the method is demonstrated for two reservoirs in Wyoming. The unit is jointly supported by the University of Wyoming, the Wyoming Game and Fish Department, and the US Fish and Wildlife Service.