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A one-dimensional (1D) hydrologic-hydraulic model for simulating dual drainage in urban areas is presented. It consists of four modules: (1) rainfall-runoff transformation, (2) 1D flow routing on a street network, (3) flow interception at street inlets, and (4) flow interaction between surface water on the streets and the underground storm-water system by interfacing with the EPA-SWMM5 engine (U.S. Environmental Protection Agency-Storm Water Management Model). The hydrologic model (first module) transforms rainfall to runoff using the kinematic wave approximation and simulates the infiltration process with the Green-Ampt method. The street network model (second module) is based on a finite-volume shock-capturing scheme that solves the fully conservative Saint-Venant equations and can be used to model both subcritical and supercritical flows. The inlet model (third module) computes the amount of water intercepted by inlets. The formulation of boundary conditions at the street crossings is generalized and can be used for any number of streets, any combination of inflowing and outflowing streets, and flow regime (e.g., subcritical and supercritical flows). Flow interaction between surface water on the streets and underground storm-water system is achieved by interfacing the proposed model with EPA-SWMM5. This interaction allows flow to enter from streets to the underground storm-water system and vice versa. The proposed model has several potential applications such as the identification of critical zones for flooding (e.g., zones with high water depths and flow velocities) in urban developments and can be used to take appropriate measures for drainage control (e.g., to increase number and/or size of inlets), to determine the consequences of different degrees of inlet clogging, and to assess flooding hazards through the application of suitable hazard criteria. A summary of criteria used for storm-water hazard assessment is presented. To demonstrate the dual-drainage model's potential, an application is performed in a catchment of the metropolitan area of Chicago, Illinois. The results obtained are promising and show that the model can be a useful tool for storm-water management and flooding hazard assessment in urban areas. [ABSTRACT FROM AUTHOR]

Acoustic Doppler current profilers (ADCPs) are commonly used to measure streamflow and water velocities in rivers and streams. This paper presents laboratory, field, and numerical model evidence of errors in ADCP measurements caused by flow disturbance. A state-of-the-art three-dimensional computational fluid dynamic model is validated with and used to complement field and laboratory observations of flow disturbance and its effect on measured velocities. Results show that near the instrument, flow velocities measured by the ADCP are neither the undisturbed stream velocity nor the velocity of the flow field around the ADCP. The velocities measured by the ADCP are biased low due to the downward flow near the upstream face of the ADCP and upward recovering flow in the path of downstream transducer, which violate the flow homogeneity assumption used to transform beam velocities into Cartesian velocity components. The magnitude of the bias is dependent on the deployment configuration, the diameter of the instrument, and the approach velocity, and was observed to range from more than 25% at 5 cm from the transducers to less than 1% at about 50 cm from the transducers for the scenarios simulated. [ABSTRACT FROM AUTHOR]

Self-burial of finite-length cylinders under pure oscillatory flow was studied with a large oscillating water-sediment tunnel (LOWST). Cylindrical models were placed on a 60 cm deep sandy bed and measurements of cylinder burial were made with the aid of video cameras. Thirty experiments were completed for a wide range of flow conditions to investigate burial due to scour of cylinders having length-to-diameter ratios between two and four. Experimental results showed a strong correlation between the Shields parameter and the equilibrium burial depth. On the other hand, the correlation between the equilibrium burial depth and the Keulegan-Carpenter number, commonly used to determine equilibrium scour depth of pipelines, was found to be less strong for the current case of short cylinders. Length-to-diameter ratio, density, and initial burial of the models were not found to influence the equilibrium burial depth. A time interval, necessary for burial initiation, was defined. The time scale for the burial of a cylindrical object was also identified and characterized by a semiempirical equation. Based on the observations, a new equation to estimate the burial of finite-length cylinders is advanced and a procedure to estimate the burial process is proposed. [ABSTRACT FROM AUTHOR]

The capability of acoustic Doppler velocimeters to resolve flow turbulence is analyzed. Acoustic Doppler velocimeter performance curves (APCs) are introduced to define optimal flow and sampling conditions for measuring turbulence. To generate the APCs, a conceptual model is developed which simulates different flow conditions as well as the instrument operation. Different scenarios are simulated using the conceptual model to generate synthetic time series of water velocity and the corresponding sampled signals. Main turbulence statistics of the synthetically generated, sampled, and nonsampled time series are plotted in dimensionless form (APCs). The relative importance of the Doppler noise on the total measured energy is also evaluated for different noise energy levels and flow conditions. The proposed methodology can be used for the design of experimental measurements, as well as for the interpretation of both field and laboratory observations using acoustic Doppler velocimeters. [ABSTRACT FROM AUTHOR]

The article presents discussions on articles related to hydraulic engineering. According to the author, the calculation scheme for Einstein Integrals has been proposed on the foundation of the work of one author. The new suggested algorithm can be applied in morphodynamic models. On the other hand, calculation for roughness factor for laminar flows by the use of the method stated in the equation has not been effective on the simulated results.