Due to the lack of data on hydraulic-jump dynamics in very large channels, the present paper describes the main characteristics
of the velocity field and turbulence in a large rectangular channel with a width of 4 m. Although a hydraulic jump is always
treated as a wave that is transversal to the channel wall, in the case of this study it has a trapezoidal front shape, first
starting from a point at the sidewalls and then developing downstream in an oblique manner, finally giving rise to a trapezoidal
shape. The oblique wave front may be regarded as a lateral shockwave that arises from a perturbation at a certain point of
the lateral wall and travels obliquely toward the centreline of the channel. The experimental work was carried out at the
Coastal Engineering Laboratory of the Water Engineering and Chemistry Department of the Technical University of Bari (Italy).
In addition to the hydraulic jump formation, a large recirculating flow zone starts to develop from the separating point of
the lateral shock wave and a separate boundary layer occurs. Intensive measurements of the streamwise and spanwise flow velocity
components along one-half width of the channel were taken using a bidimensional Acoustic Doppler Velocimeter (ADV). The water
surface elevation was obtained by means of an ultrasonic profiler. Velocity vectors, transversal velocity profiles, turbulence
intensities and Reynolds shear stresses were all investigated. The experimental results of the separated boundary layer were
compared with numerical predictions and related work presented in literature and showed good agreement. The transversal velocity
profiles indicated the presence of adverse pressure gradient zones and the law of the wall appears to govern the region around
the separated boundary layer. 相似文献
ABSTRACT: Statutory and case law at the state level provide critical legal frameworks for water management. As many state governments struggle to improve efficiency in water management and resolve conflicts over water usage, they must continually assess the efficacy of their state water law. Most states have water laws that are disconnected and overlapping. This article presents a methodology to assess state water law and take first steps toward a comprehensive state water resources act. The methodology is driven by issues and conflicts in water management. It synthesizes management and legal analyses into a process that incorporates the diverse perspectives of state water stakeholders. The results of the analysis are identification of management issues, profiles of state water law, and explorations of legal options that are available to the state government. Illinois is provided as a case study for this methodology. 相似文献
Objective: The annual rate of impaired driving crashes in the United States has remained nearly constant over the last decade. While engineers, educators, enforcement, and emergency response personnel have worked diligently in their combined efforts to reduce the loss of life, there is still significant progress to be made. One area of recent interest is the use of data driven enforcement. The basis for data driven enforcement is the use of statistical clustering to identify geographic areas that represent the location of problem identification for various criminal or traffic offenses. In the case of impaired driving fatalities, the clustering represents locations with high rates of impaired driving crashes. Law enforcement officers and supervisors may allocate resources towards more specifically and efficiently addressing problem areas.
Methods: While data driven enforcement has been proven to be an effective tool in addressing crime and traffic safety problems, it has been a slow process for agencies to adopt data driven techniques. This study aims to explore the difference in traffic stops made inside and outside of hotspot identified areas. The study uses data from the Stark County Operating a Vehicle Impaired Task Force between 2013 and 2014.
Results: The analysis determined that stop occurring in hotspot defined areas are more likely to result in impaired driving arrests and seatbelt citations. Additionally it is found that the average cost of impaired driving arrests is significantly cheaper for stops occurring inside of hotspot areas.
Conclusion: Clustering as a means of directing law enforcement efforts are a way to increase the productivity and benefits of law enforcement agencies with limited finances or personnel. From this study it is seen that traffic stops made within defined cluster or hot spot areas are more effective in resulting in OVI arrests. 相似文献