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As the classical water-supply looped-network optimization problem is mathematically nonconvex and multimodal, the resulting solution of most approaches is uncertain in the sense of how close it is to the "best" solution. In many cases, this "best"' or "global" solution is invoked and pursued without a clear understanding of its meaning. This paper discusses what is involved in "global" solutions and the role that pipe flow distribution can play to deal with nonconvexity and multimodality in a new context. The author has introduced this new context recently after formulating a new objective function capable of finding that a looped network can be economically more attractive than its related branched one. Therefore, the convenience of an approach dealing with flows and heads, as relevant decision variables, is encouraged in this paper and its advantages enumerated under the new concepts. The entropy approach is studied critically and an example is provided for comparison with the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper a historical analysis of two fundamental aspects of hydraulic engineering is made. They are the construction of works and engineering teaching in Cuban context. Evolution of construction and its influence in the formation of professionals can be appreciated. Also, the presence of this professionals has influenced the amount and complexity of works. Here, some social and environmental factors are mentioned, establishing an ancient memory, which has been divided into five parts withholding five centuries. On each part development of works and teaching of this engineering are presented, thus making a historical - logical link between them. [ABSTRACT FROM AUTHOR]

The 21st century company faces a new complex economic, cultural and informational scenario. The Cuban management system, following governmental regulations, enforces public enterprise approach to innovation and technology management (ITM). In contrast to the above, the Enterprise for Hydraulic Projects and Investigations in Villa Clara (EIPH-VC) does not have any systematic management action in this sense to improve its general performance. This paper presents the theoretical and methodological approach to systematize the ITM and the first results of its implementation, derived from an incipient but systematic application of the ITM in this company, characterized by the intensive use of knowledge and technology. [ABSTRACT FROM AUTHOR]

The designers of road (highway) cross-drainage structures frequently use culverts instead of bridges. However, culvert design is usually characterized by some conceptual errors which persist without modification because of lack of critical analysis and knowledge of useful experiences. In this paper, the proposed solution attempts to offer a novel type of hydraulic low cost structures for conveying the surface water through and over the embankment as well as fulfilling the following: first, for the design discharge the culvert suffers no damage to the embankment nor to the pavement and, second, in case the discharge increases the water is allowed to flow over the pavement (embankment) without damage; naturally the traffic would suffer a short interruption. [ABSTRACT FROM AUTHOR]

The paper shows the experience in handling the design of Caibarien- Santa Maria key causeway to fit it with the environmental characteristics of the watershed in which it is located. By means of a cause-effect modeling graphic, corroborated by an up-dated informatics software, it is demonstrated the fundamental character that keeping the ocean-island shelf interchange has, as well as the hydrodynamics, in the preservation of the marine environmental characteristics. It is also explained the general strategy that was followed, on the assumption that the causeway is, according to the environmental point of view, a hydraulic construction as a set of its main components: the road layout, the calculation of bridges by hydraulically quasi-homogenous sections, the manner the bridges are located, the off-road induced works and the so-called ecological bridges. [ABSTRACT FROM AUTHOR]

This paper describes an experience in the use of mathematical models and load tests on hydrotechnical structures. The results obtained from the load test performed on the sheet pile of a dock, located in the eastern part of Cuba, are presented. Horizontal and vertical deformations were measured. A comparison is made between the theoretical methods for deformation calculation and the mathematical methods based on the finite-element method. Finally, the coincidence of results obtained from the numerical model and those of a real-scale load test is proved, thus showing that deformations could not become a risk if the dock is subject to a new load system. [ABSTRACT FROM AUTHOR]

Teaching in Hydraulics is based on theoretical equations and empirical solutions given by researchers. Also results from physical and mathematical models are used. But not always flow behavior can be clearly visualized or, as with physical models, specialized laboratories are required. Therefore, a tool is needed to reproduce, in quality and quantity, the movement of fluids across different types of conduits. This paper deals, for the first time in Cuba, with the application of visual models to visualize flow behavior under different situations. By applying the visual modeling software Flow-3D, solutions to flow problems in channels and pipes can be visually observed, thus enhancing the teacher's action. Also student comprehension is highly improved as he can watch different alternatives of flow under various working conditions. [ABSTRACT FROM AUTHOR]

Water resources systems usually integrate a group of components or subsystems, each with their own set of inputs and outputs. Operating these systems is a continuous process that should be rigorously controlled to insure objectives and goals. The main aspects to be developed for monitoring and studying hydraulic systems operation are: the equipment for acquisition of system variables which characterize its performance and the implementation of software tools to facilitate interpretation of gathered data. In this paper a technology for field variables logging, in deferred time, developed by Hydraulic Resources Group of the Hydraulic Research Center, is presented. Additionally, WinRM application results to Santa Lucía Aqueduct and Sewer Enterprise for water control and management activity support are included. [ABSTRACT FROM AUTHOR]

In supercritical flow canals it is very important to consider the air - entrainment phenomenon. This phenomenon is needed for the hydraulic design of the canal wall height. In this paper a comparison is made between several existing methods for the air - entrainment determination and a new simpler method is proposed which appears to be as trustable as the best of the existing ones. [ABSTRACT FROM AUTHOR]

The hydraulic jump in circular conduits has not been studied in depth. Some reports even consider that theroretical values of its parameters are not in agreement with the few experimental data available. Theoretical treatment of the problem is hereby presented with calculation expressions and graphics for its solution. Validity of the results is shown provided that all involved coefficients are correctly fundamented. To this end reported test results in the literature are re-elaborated. Comparison between proposed approximate formulas to calculate jump length and an empirical dependence existing within hydraulic properties of these conduits, shows the need to apply the latter in order to obtain reliable results. The paper also calculates the hydraulic jump efficiency in consumption of the excess energy in these conduits. [ABSTRACT FROM AUTHOR]

The exponential law of flow is revised through dimensional analysis leading to the determination of hydraulic conductivity (HC). But HC depends on the gradient exponent which has limited the use of the exponential law in practice. The paper shows how the velocity can be calculated given the gradient and the properties. A general relationship between hydraulic conductivity and that of Darcy is derived as a function only of the exponent and the gradient. Besides, an excellent correlation is obtained between a gradient quotient (hydraulic over Darcy critical) and the exponent of the gradient in the exponential law, derived from extensive data of experimental results of many authors. Lastly, a correlation between Darcy critical hydraulic gradient and intrinsic permeability is made to estimate Darcy critical gradient when no information is available about the media equivalent roughness. [ABSTRACT FROM AUTHOR]

Geographic information systems (GIS) are an important tool for storing and managing geographically referenced data. They can represent real world through digital data and data from simulation of natural or antropic processes over a given scenario for a given time. GIS has multiple applications. It is widely used in hydraulics and nowadays many resource management systems are incorporating applications. In the Centro de Investigaciones Hidráulicas (CIH) of CUJAE a platform is developed for water resources management. One of its components is GIS. In this paper general characteristics of GIS are explained, development tools and the specifically designed GIS for the Modular Integrated Platform of water resources. [ABSTRACT FROM AUTHOR]

Looped networks have been used extensively in practice with the advantage of reducing the amount of affected users under a failure situation. The concept of reliability is applied as an attempt to measure quantitatively the possibility of keeping an adequate service level for a given time horizon. From the above, one should expect a looped network to be more reliable than a branched network under similar layout and sizing characteristics. In this paper two quantitative indices to measure expected network behavior are discussed: reliability and tolerance. These indices are calculated and a comparison is made between looped and branched networks. [ABSTRACT FROM AUTHOR]

Ski – jump energy dissipators are widely used in practice because of their well – known effectiveness. Nevertheless, some uncertainty exists associated with the dimensions of the scour – hole appearing downstream of the structure. In this paper a new method is presented in which this problem is solved. This method includes the spillway stability checking as part of the design process and also the stability checking of any other construction near the zone of energy dissipation. Finally, a methodology is suggested for the design of these dissipating structures which includes considering discharges below the design discharge. [ABSTRACT FROM AUTHOR]