scholarly journals Evaluating Efficiency Improvement of Deep-Cut Curb Inlets for Road-Bioretention Stripes

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3368
Author(s):  
Xiaoning Li ◽  
Chuanhai Wang ◽  
Gang Chen ◽  
Qiang Wang ◽  
Zunle Hu ◽  
...  
Keyword(s):  
Flow Simulation ◽  
Urban Drainage ◽  
Two Dimensional ◽  
Efficiency Improvement ◽  
Sponge City ◽  
The Road ◽  
Wide Range ◽  
Two Dimensional Flow ◽  
Simulation Results

Making a deep cut on the curb inlet has been used in some sponge-city (SPC) projects for road-bioretention stripes to manage stormwater runoff since they were easily implemented in the field. The efficiencies of the deep-cut curb inlets in those projects were unknown for lacking equation to evaluate their efficiencies. Two kinds of retrofit scenarios are commonly used: (1) The curb-cut cases when the deep cut is made only over the width of the curb inlet; (2) the road-curb cut cases when both the curb inlet and a small part of the road surface have a deep cut. An updated two-dimensional flow simulation program, FullSWOF-ZG, was used to determine two important parameters in road curb inlet design: The 100% interception curb inlet lengths (LT) and the curb inlet efficiencies (Eci). Eight-hundred retrofit modeling cases were compared with the no-cut cases to quantify the efficiency improvement of the deep-cut curb inlets. The simulation results show both LT and Eci of the curb-cut cases do not improve much. This case study with limited combinations of longitudinal and cross slopes and inlet lengths demonstrated that Eci of the road-curb cut cases improves to a large extent so that they can be used in the SPC projects and other urban drainage projects to reduce the flooding potentials. A general equation used to design and evaluate the road-curb cut inlets can be developed based on more simulation cases with a wide range of input parameters in a future study.

scholarly journals Evaluating Curb Inlet Efficiency for Urban Drainage and Road Bioretention Facilities

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 851 ◽  
Author(s):  
Li ◽  
Fang ◽  
Chen ◽  
Gong ◽  
Wang ◽  
...  
Keyword(s):  
Overland Flow ◽  
Flow Simulation ◽  
Linear Regression Method ◽  
Urban Drainage ◽  
Regression Equations ◽  
Strongly Correlated ◽  
Wide Range ◽  
Input Parameters ◽  
Longitudinal Slope ◽  
Two Dimensional Flow

An updated two-dimensional flow simulation program, FullSWOF-ZG, which fully (Full) solves shallow water (SW) equations for overland flow (OF) and includes submodules modeling infiltration by zones (Z) and flow interception by grate-inlet (G), was tested with 20 locally depressed curb inlets to validate the inlet efficiency (Eci), and with 80 undepressed curb inlets to validate the inlet lengths (LT) for 100% interception. Previous curb inlet equations were based on certain theoretical approximations and limited experimental data. In this study, 1000 road-curb inlet modeling cases from the combinations of 10 longitudinal slopes (S0, 0.1–1%), 10 cross slopes (Sx, 1.5–6%), and 10 upstream inflows (Qin, 6–24 L/s) were established and modeled to determine LT. The second 1000 modeling cases with the same 10 S0 and 10 Sx and 10 curb inlet lengths (Lci, 0.15–1.5 m) were established to determine Eci. The LT and Eci regression equations were developed as a function of input parameters (S0, Sx, and Qin) and Lci/LT with the multiple linear regression method, respectively. Newly developed regression equations were applied to 10,000 inlet design cases (10 S0, 10 Sx, 10 Qin, and 10 Lci combinations) and comprehensively compared with three equations in previous studies. The 100% intercepted gutter flow (Qg100) equations were derived, and over-prediction of Qg100 from previous methods was strongly correlated to smaller S0. Newly developed equations gave more accurate estimations of LT and Eci over a wide range of input parameters. These equations can be applied to designing urban drainage and road bioretention facilities, since they were developed using a large number of simulation runs with diverse input parameters, but previous methods often overpredict the gutter flow of total interception when the longitudinal slope S0 is small.

scholarly journals Simplified Simulation Method for Flood-Induced Bend Scour—A Case Study Near the Shuideliaw Embankment on the Cho-Shui River

2017 ◽  
Author(s):  
Wen-Dar Guo ◽  
Jian-Hao Hong ◽  
Cheng-Hsin Chen ◽  
Chih-Chiang Su ◽  
Jihn-Sung Lai
Keyword(s):  
Flow Simulation ◽  
Field Measurements ◽  
Practical Method ◽  
Simulation Method ◽  
Water Levels ◽  
Two Dimensional ◽  
Short Term ◽  
Common Causes ◽  
Two Dimensional Flow

The modeling of flood-induced bend scour near embankment toes can provide important information for river engineering, embankment safety warnings, and emergency action management. During the rainy seasons, short-term general scour and bend scour are the most common causes for the failure of reinforced concrete embankments in Taiwan. To gain a deeper understanding of the scouring process near levee foundations, this study proposed a straightforward and practical method for bend scour simulation. The proposed simulation method is subdivided into three stages: two-dimensional flow simulation, general scour estimation, and bend scour estimation. A new bend-scour computation equation is proposed and incorporated into a two-dimensional hydraulic finite-volume model for simulating the evolution of bend scour depth around embankment toes. The proposed method is applied to simulate the temporal evolution of bend scouring near the Shuideliaw Embankment on the Cho-Shui River in Taiwan, where serious failure occurred during the June 2012 monsoon. Field data were gathered using the numbered-brick technique at the Shuideliaw Embankment to demonstrate the accuracy of the proposed method. The results of the bend scour simulations compared reasonably well with field measurements, indicating close agreement in terms of water levels and bend scour depths near the Shuideliaw Embankment. The proposed method was found to quickly estimate the maximum short-term general scour and bend scour depths for further enhancement of the safety of the embankment toe.

scholarly journals An Arterial Signal Coordination Optimization Model for Trams Based on Modified AM-BAND

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yangfan Zhou ◽  
Shunping Jia ◽  
Baohua Mao ◽  
Tin Kin Ho ◽  
Wei Wei
Keyword(s):  
Performance Indicators ◽  
Optimization Model ◽  
Road Network ◽  
Signal Coordination ◽  
The Road ◽  
Traffic Performance ◽  
Minimum Bandwidth ◽  
Band Method ◽  
Simulation Results

Modern trams are developing fast because of their characteristics like medium capability and energy saving. Exclusive way is always set in practice to avoid interruption from general vehicles, while trams have to stop at intersections frequently due to signal rules in the road network. Therefore, signal optimization has great effects on operational efficiency of trams system. In this paper, an arterial signal coordination optimization model is proposed for trams progression based on the Asymmetrical Multi-BAND (AM-BAND) method. The AM-BAND is modified from the following aspects. Firstly, BAM-BAND is developed by supplementing active bandwidth constraints to AM-BAND. Assisted by the IBM ILOG CPLEX Optimization Studio, two arterial signals plans with eight intersections are achieved from AM-BAND and BAM-BAND for comparison. Secondly, based on the modified BAM-BAND, a BAM-TRAMBAND model is presented, which incorporates three constraints regarding tram operations, including dwell time at stations, active signal priority, and minimum bandwidth value. The case study and VISSIM simulation results show that travel times of trams decrease with signal plan from BAM-TRAMBAND comparing with the original signal plan. Moreover, traffic performance indicators such as stops and delay are improved significantly.

The Prediction of Turbulent, Supersonic, Two-Dimensional, Boundary-Layer Flows

1971 ◽  
Vol 22 (3) ◽  
pp. 274-294 ◽  
Author(s):  
S. Sivasegaram ◽  
J. H. Whitelaw
Keyword(s):  
Experimental Data ◽  
Turbulent Energy ◽  
Two Dimensional ◽  
Boundary Layer Flows ◽  
Adiabatic Wall ◽  
Mean Velocity ◽  
Wide Range ◽  
Two Dimensional Flow ◽  
Dimensional Boundary ◽  
Flow Configurations

SummaryThe prediction procedures of Bradshaw and Ferriss and Spalding and Patankar are compared with a wide range of experimental data obtained in turbulent, supersonic, two-dimensional flow. Both procedures are shown to result in satisfactory predictions of mean velocity profiles and wall shear stress in adiabatic-wall situations: in addition, the procedure of Spalding and Patankar is shown to be satisfactory in heat transfer situations. The Bradshaw and Ferriss procedure employs a turbulent energy hypothesis in contrast to the mixing-length assumptions used in the present version of the Spalding and Patankar procedure. The close agreement between the predictions of the two procedures indicates a lack of experimental data obtained in flow configurations with suddenly imposed or relaxed pressure gradients.

scholarly journals Two-Dimensional Computational Model for Wave Rotor Flow Dynamics

1997 ◽  
Vol 119 (4) ◽  
pp. 978-985 ◽  
Author(s):  
G. E. Welch
Keyword(s):  
Stokes Equations ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Wave Rotor ◽  
Navier Stokes Equations ◽  
Flow Features ◽  
Rotor Experiment ◽  
Two Dimensional Flow ◽  
Rotor Flow

A two-dimensional (θ, z) Navier–Stokes solver for multiport wave rotor flow simulation is described. The finite-volume forms of the unsteady thin-layer Navier–Stokes equations are integrated in time on multiblock grids that represent the stationary inlet and outlet ports and the moving rotor passages of the wave rotor. Computed results are compared with three-port wave rotor experimental data. The model is applied to predict the performance of a planned four-port wave rotor experiment. Two-dimensional flow features that reduce machine performance and influence rotor blade and duct wall thermal loads are identified.

Dynamic Pore-Network Simulator for Modeling Buoyancy-Driven Migration During Depressurization of Oil-Saturated Systems

SPE Journal ◽  
2010 ◽  
Vol 15 (04) ◽  
pp. 906-916 ◽  
Author(s):  
C.C.. C. Ezeuko ◽  
S.R.. R. McDougall ◽  
I.. Bondino ◽  
G.. Hamon
Keyword(s):  
Full Range ◽  
Flow Simulation ◽  
Pore Network ◽  
Reservoir Rock ◽  
Gas Evolution ◽  
Network Simulator ◽  
Gas Migration ◽  
Gas Oil ◽  
Wide Range ◽  
Simulation Results

Summary A number of vertically oriented heavy- and light-oil-depletion experiments have been conducted in recent years in an attempt to investigate the effect of gravitational forces on gas evolution during solution-gas drive. Although some experimental results indirectly suggest the occurrence of gas migration during these tests (especially at slow depletion rates), a major limitation of such an interpretation is the difficulty in visualizing the process in reservoir-rock samples. In contrast, experimental observations using transparent glass models have proved invaluable in this context and provide a sound physical basis for modeling gravitational gas migration in gas/oil systems. However, the experimental observations often exhibit somewhat contradictory trends—some studies showing dispersed gas migration, while others describe fingered, channelized flow—and, to date, there appears to have been little systematic effort toward modeling the wide range of behaviors seen in or inferred from laboratory tests. To this end, we present a new pore-network simulator that is capable of modeling the time-dependent migration of growing gas structures. Multiple pore-filling events are modeled dynamically with interface tracking allowing the full range of migratory behaviors to be reproduced, including braided migration (i.e., discontinuous flow of gas through narrow channels) and discontinuous dispersed flow. Simulation results are compared with experiments and are found to be in excellent agreement. Moreover, simulation results clearly show that a number of network and fluid parameters interact in a rather complex manner and, as a consequence, the competition between capillarity and buoyancy produces different gas-evolution patterns during pressure depletion. The implications of evolution regime on recovery from gas/oil systems undergoing depressurization are discussed extensively.

scholarly journals Turbulent 2.5-dimensional dynamos

2016 ◽  
Vol 799 ◽  
pp. 246-264 ◽  
Author(s):  
K. Seshasayanan ◽  
A. Alexakis
Keyword(s):  
Turbulent Flows ◽  
Large Scale ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Wide Range ◽  
Two Dimensional Flow

We study the linear stage of the dynamo instability of a turbulent two-dimensional flow with three components $(u(x,y,t),v(x,y,t),w(x,y,t))$ that is sometimes referred to as a 2.5-dimensional (2.5-D) flow. The flow evolves based on the two-dimensional Navier–Stokes equations in the presence of a large-scale drag force that leads to the steady state of a turbulent inverse cascade. These flows provide an approximation to very fast rotating flows often observed in nature. The low dimensionality of the system allows for the realization of a large number of numerical simulations and thus the investigation of a wide range of fluid Reynolds numbers $Re$, magnetic Reynolds numbers $Rm$ and forcing length scales. This allows for the examination of dynamo properties at different limits that cannot be achieved with three-dimensional simulations. We examine dynamos for both large and small magnetic Prandtl-number turbulent flows $Pm=Rm/Re$, close to and away from the dynamo onset, as well as dynamos in the presence of scale separation. In particular, we determine the properties of the dynamo onset as a function of $Re$ and the asymptotic behaviour in the large $Rm$ limit. We are thus able to give a complete description of the dynamo properties of these turbulent 2.5-D flows.

Hydrodynamics Loads on Two Degree-of-Freedom Cylinder With Uncertain Natural Frequencies Subject to VIV

2009 ◽  
Author(s):  
Didier Lucor
Keyword(s):  
Natural Frequencies ◽  
Numerical Study ◽  
Spectral Element ◽  
Numerical Approach ◽  
Response Surfaces ◽  
Degree Of Freedom ◽  
Two Dimensional ◽  
Wide Range ◽  
Two Dimensional Flow ◽  
Two Degree Of Freedom

In this numerical study, we build response surfaces of two degree-of-freedom vortex-induced vibrations (VIV) of flexibly mounted cylinders for a wide range of transverse and in-line natural frequencies. We consider both the structure and the flow to be two-dimensional and the structure has a low mass damping. The emphasis is put on the representation of the hydrodynamic loads acting on the cylinder in response to the change in the natural frequencies of the structure. The system is sampled for a wide range of natural frequencies within the synchronization region, totaling 149 two-dimensional flow-structure simulations. The parametric range of the in-line frequency is chosen to be larger than the one of the transverse frequency in order to favor multi-modal responses. No preferred frequencies are emphasized within the intervals of study. The fully spectral numerical approach relies on a stochastic collocation method coupled to a spectral element-based deterministic solver.

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