scholarly journals Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 458
Author(s):  
Drew C. Baird ◽  
Benjamin Abban ◽  
S. Michael Scurlock ◽  
Steven B. Abt ◽  
Christopher I. Thornton
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Numerical Models ◽  
Hydraulic Performance ◽  
Physical Models ◽  
Protection Measures ◽  
Design Engineers ◽  
Model Study ◽  
Study Results ◽  
Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

Accelerating Climate Model Computation by Neural Networks: A Comparative Study

2021 ◽  
Author(s):  
Maha Mdini ◽  
Takemasa Miyoshi ◽  
Shigenori Otsuka
Keyword(s):  
Neural Networks ◽  
Computational Complexity ◽  
Statistical Model ◽  
Physical Model ◽  
Climate Model ◽  
Numerical Models ◽  
Computation Time ◽  
High Accuracy ◽  
Physical Models ◽  
Computer Resources

<p>In the era of modern science, scientists have developed numerical models to predict and understand the weather and ocean phenomena based on fluid dynamics. While these models have shown high accuracy at kilometer scales, they are operated with massive computer resources because of their computational complexity.  In recent years, new approaches to solve these models based on machine learning have been put forward. The results suggested that it be possible to reduce the computational complexity by Neural Networks (NNs) instead of classical numerical simulations. In this project, we aim to shed light upon different ways to accelerating physical models using NNs. We test two approaches: Data-Driven Statistical Model (DDSM) and Hybrid Physical-Statistical Model (HPSM) and compare their performance to the classical Process-Driven Physical Model (PDPM). DDSM emulates the physical model by a NN. The HPSM, also known as super-resolution, uses a low-resolution version of the physical model and maps its outputs to the original high-resolution domain via a NN. To evaluate these two methods, we measured their accuracy and their computation time. Our results of idealized experiments with a quasi-geostrophic model [SO3] show that HPSM reduces the computation time by a factor of 3 and it is capable to predict the output of the physical model at high accuracy up to 9.25 days. The DDSM, however, reduces the computation time by a factor of 4 and can predict the physical model output with an acceptable accuracy only within 2 days. These first results are promising and imply the possibility of bringing complex physical models into real time systems with lower-cost computer resources in the future.</p>

Physical Model Study of Chicago's New Calumet Influent Pumping Station

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
D. Brocard ◽  
M. Garcia ◽  
T. Kunetz ◽  
J. Sobanski ◽  
A. Waratuke ◽  
...  
Keyword(s):  
Physical Model ◽  
Air Entrainment ◽  
Design Guidelines ◽  
Water Levels ◽  
Maintenance Cost ◽  
Optimized Design ◽  
Original Design ◽  
Pumping Station ◽  
Model Study ◽  
Wide Range

A new raw wastewater influent pumping station was designed for the Calumet Water Reclamation Plant in Chicago. The new station could not be designed to be in full compliance with design guidelines of the Hydraulic Institute due to site constraints. Proper operation of the pumping station and optimum operational flexibility are goals for the successful long term performance of the new station. A physical model study was used to identify deficiencies in the original design relative to flow characteristics. The model enabled development of design modifications to address hydraulic flow deficiencies. The optimized design resulted in pump approach flow conditions that provide proper pump performance under a wide range of varying water levels and different combinations of operating pumps and screen channels. Other benefits of the model included improvement in pump efficiency, lack of air entrainment, decreased pump wear, and decreased scour of concrete surfaces. Optimized design also results in operation and maintenance cost savings which, in the long run, will greatly surpass the cost of the physical model study. The required elements to optimize the performance were integrated with the design of the facility, thereby avoiding potentially costly retrofits if the deficiencies had not been mitigated prior to construction.

Rough River Outlet Works physical model study

2021 ◽  
Author(s):  
Jeremy Sharp ◽  
Locke Williams ◽  
Duncan Bryant ◽  
Jake Allgeier ◽  
Kevin Pigg ◽  
...  
Keyword(s):  
Physical Model ◽  
Hydraulic Performance ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Structure Transition ◽  
Us Army ◽  
Model Study ◽  
Design Changes ◽  
The Us ◽  
Hydraulics Laboratory

The US Army Corps of Engineers, Louisville District, requested the support and assistance of the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (CHL), in the evaluation of the hydraulic performance of the replacement Outlet Works for Rough River Dam. To support the design effort, CHL constructed a 1:25.85 scale physical model. The proposed features of the model in the domain are the curved approach channel, intake structure, transition, curved conduit, stilling basin, concrete apron, and retreat channel. Tests performed to evaluate the hydraulic performance illuminated a few design concerns. To address these issues, several key design changes were made. These included the retreat channel slope, end sill design, and transition design.

Application of Genetic Programming for Estimation of Soil Compaction Parameters

2011 ◽  
Vol 147 ◽  
pp. 70-74 ◽  
Author(s):  
Navid Naderi ◽  
Pedram Roshani ◽  
Masoud Zabihi Samani ◽  
Mohammad Amin Tutunchian
Keyword(s):  
Genetic Programming ◽  
Numerical Models ◽  
Soil Classification ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Model Study ◽  
Linear Behavior ◽  
Soft Computing Method ◽  
Study Results ◽  
Input Variables

The aim of this study is to propose two numerical models by a well-known soft computing method, Genetic Programming (GP), for the estimation of soils compaction parameters. Genetic Programming is a pattern recognition approach that has the ability of modeling the non-linear behavior of complex engineering problems. The input variables were the soil classification properties, and the outputs were the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD). To provide model, a database including properties of different soils classified as CH, CI, CL, GC, GM, MH, MI, ML and SC was used. In addition, a new Multiple Linear Regression (MLR) based formula using the database, compared with the GP based model. Study results revealed that the proposed formula by GP can predict the compaction parameters of soils in a highly precise manner, and its outputs were in satisfactory conformity with real test results. Performances of the proposed models evaluated using the regression statistical analyses. The proposed formulae can be useful for the preliminary design of engineering projects and are more useful for cases with time and financial limitations.

The Effects of Constructing a Barrage across the Tawe Estuary

1984 ◽  
Vol 16 (3-4) ◽  
pp. 463-475
Author(s):  
T W Broyd ◽  
A G Hooper ◽  
R S W M Kingsbury
Keyword(s):  
Physical Model ◽  
Model Calibration ◽  
Numerical Models ◽  
Physical Models ◽  
Biological Information ◽  
Flow Conditions ◽  
Field Surveys ◽  
Physical Chemical ◽  
South Wales ◽  
Remedial Actions

A proposed barrage across the tidal reaches of the R. Tawe, South Wales, was modelled to simulate its effect on the environment. Both computer and physical models were prepared, tested and run for a variety of tidal and fresh water flow conditions. A comprehensive data review identified further information essential for model calibration and information. Field surveys to gather physical, chemical and biological information were performed as part of the overall study. The numerical models predicted hydrodynamic and pollutant behaviour upstream of the barrage and sedimentation effects downstream. The physical model was used for navigational effects and for identifying problems during the construction phase. The study revealed that conditions would change but not significantly deteriorate provided that certain remedial actions were taken.

3-D Transient CFD Modeling of Pig Motion

2016 ◽  
Author(s):  
Diego Jaimes Parilli ◽  
Nelson Loaiza ◽  
Janneth García ◽  
Armando Blanco
Keyword(s):  
Pressure Drop ◽  
Numerical Models ◽  
Control Volume ◽  
Physical Models ◽  
Body Motion ◽  
Cfd Modeling ◽  
Maximum Pressure ◽  
Variable Boundary ◽  
Numerical Predictions ◽  
Wide Range

Pigging operations are common procedures for pipeline maintenance. However, questions still remain about pig dynamics due to the difficulties to accurately describe this complex phenomenon. Consequently, most predictions of pig dynamics are based on empirical knowledge deduced from experimental data and numerical models developed considering simplified physical models, without calculate transient pig-flow interaction and neglecting 3D aspect of flow dynamics. Therefore, to present an actual 3D transient model, this paper proposes a novel CFD methodology using a static mesh in a moving control volume. Forces acting on the pig are dynamically computed by a Fluid-Structure Interaction (FSI) approach; pig velocity is obtained for each time instant and it is set as a variable boundary condition. This method was validated with experimental results and it may be used to describe a wide range of rigid body motion immerse in a flow. This approach is then utilized to obtain the transient simulation of a pig launch in a straight water pipeline. Numerical predictions of the static grid method were compared with those obtained using moving mesh simulations. Results show that the pig reaches a terminal velocity higher than average flow velocity and a huge difference on predictions of maximum pressure drop (through the pig) between steady state based models and transient models. Additionally, it was simulated a 2D model to observe the differences between 2D and 3D simulations on the flow characteristics and pig motion features, which shows an important increase of the pressure drop on 3D model over 2D and high pig acceleration in the 3D simulation.

scholarly journals Accuracy of boundary layer treatments at different Reynolds scales

2020 ◽  
Vol 10 (1) ◽  
pp. 295-310
Author(s):  
Nicolás D. Badano ◽  
Angel N. Menéndez
Keyword(s):  
Scale Effects ◽  
Numerical Models ◽  
Physical Models ◽  
Wall Friction ◽  
Navier Stokes ◽  
Parallel Plates ◽  
Scale Free ◽  
Head Losses ◽  
Wide Range ◽  
Resistive Forces

AbstractResistive forces associated to boundary layers (‘friction’) are usually out of scale in physical models of hydraulic structures, especially in the case of hydraulically smooth walls, generating distortions in the model results known as scale effects, that can be problematic in some relevant engineering problems. These scale effects can be quantified and corrected using suitable numerical models. In this paper the accuracy of using numerical simulation through the Reynolds Averaged Navier-Stokes (RANS) approximation in order to represent the head losses introduced by friction in hydraulically smooth walls is evaluated for a wide range of Reynolds scales. This is performed by comparing the numerical results for fully developed flow on circular pipes and between parallel plates against experimental results, using the most popular wall treatments. The associated numerical errors, mesh requirements and ranges of application are established for each treatment. It is shown that, when properly applied, RANS models are able to simulate the head losses produced by smooth wall friction accurately enough as to quantify the scale effects present in physical models. A methodology for upscaling physical model results to prototype scale, free of scale effects, is proposed.

scholarly journals PREDICTION OF BEHAVIOUR OF PRESTRESSED SUSPENSION BRIDGE WITH TIMBER DECK PANELS

2017 ◽  
Vol 12 (4) ◽  
pp. 234-240 ◽  
Author(s):  
Vadims Goremikins ◽  
Dmitrijs Serdjuks ◽  
Karina Buka-Vaivade ◽  
Leonids Pakrastins ◽  
Nikolai Vatin
Keyword(s):  
Physical Model ◽  
Numerical Models ◽  
Suspension Bridge ◽  
Longitudinal Direction ◽  
Physical Models ◽  
Cross Laminated Timber ◽  
Deck Panels ◽  
Vertical Displacements ◽  
Unsymmetrical Loading ◽  
Prestressed Cable

Cable truss usage allows developing bridges with reduced requirements for girder stiffness, where overall bridge rigidity is ensured by prestressing of the stabilization cable. The advantages of prestressed suspension trusses to provide required stiffness without massive stiffness girders and the ability of cross-laminated timber to behave in both directions are combined in the analysed structure. Prestressed cable truss with coincident (unclear meaning, difficult to translate) in the centre point of the span main and stabilization cables and vertical suspenders only was considered as the main load carrying system in the considered structure of suspension bridge. Two numerical models evaluated influence of cross-laminated timber deck on the behaviour of prestressed cable truss. Two physical models of the structure with the span equal to 2 m were developed for verification of the numerical models. The first physical model was developed for the case, when panels of the deck are placed without clearances and behaving in the longitudinal direction in compression so as in the transversal direction in bending. The second physical model was developed for the case when panels of the deck are placed with clearances and are behaving in the transverse direction in bending only. The dependences of maximum vertical displacements and horizontal support reaction of the cable truss on the intensity of vertical load in cases of symmetric and unsymmetrical loading were obtained for both physical models. Possibility to decrease the cable truss materials consumption by 17% by taking into accountcombined work of prestressed cable trusses and cross-laminated timber panels was stated.

scholarly journals Experimental Analysis of Wave Overtopping: A New Small Scale Laboratory Dataset for the Assessment of Uncertainty for Smooth Sloped and Vertical Coastal Structures

2019 ◽  
Vol 7 (7) ◽  
pp. 217 ◽  
Author(s):  
Hannah E Williams ◽  
Riccardo Briganti ◽  
Alessandro Romano ◽  
Nicholas Dodd
Keyword(s):  
Time Series ◽  
Physical Model ◽  
Numerical Models ◽  
Vertical Wall ◽  
Model Tests ◽  
Physical Models ◽  
Small Scale ◽  
Wave Condition ◽  
Wave Overtopping ◽  
Physical Model Tests

Most physical model tests carried out to quantify wave overtopping are conducted using a wave energy spectrum, which is then used to generate a free surface wave time series at the wave paddle. This method means that an infinite number of time series can be generated, but, due to the expense of running physical models, often only a single time series is considered. The aim of this work is to investigate the variation in the main overtopping measures when multiple wave times series generated from the same spectrum are used. Physical model tests in a flume measuring 15 m (length) by 0.23 m (width) with an operating depth up to 0.22 m were carried out using a stochastic approach on two types of structures (a smooth slope and a vertical wall), and a variety of wave conditions. Results show variation of overtopping discharge, computed by normalising the range of the discharges at a certain wave condition with the maximum value of the discharge in the range up to 10 % , when the same wave time series is used, but this range increases to 75 % when different time series are used. This variation is found to be of a similar magnitude to both the one found with similar experiments looking at the phenomena in numerical models, and that specified by the confidence bounds in empirical methods.

VERY DEEP FACILITIES PHYSICAL MODELLING STRATEGIES

1998 ◽  
Vol 38 (1) ◽  
pp. 594
Author(s):  
J B. Hinwood ◽  
A.E. Potts ◽  
P. Sincock
Keyword(s):  
Design Process ◽  
Numerical Models ◽  
Physical Modelling ◽  
Physical Models ◽  
Dynamic Responses ◽  
Laboratory Facilities ◽  
Wide Range ◽  
Final Design ◽  
Modelling Strategies ◽  
Hull Forms

The design process for offshore facilities has used a mix of physical and numerical modelling to provide information on loads and steady dynamic responses in an efficient and accurate fashion. Usually physical modelling is used early in the design process to provide force coefficients for novel forms or novel loading conditions. Physical modelling is also used later in the design process to deal with complex issues for which the available numerical models are not adequate or are inefficient, and it is subsequently used to provide a verification of the final design under a comprehensive set of load cases.All of these applications of physical models remain important in the move to very deep water, but the limitations of water depth, plan area and velocity profile in existing laboratory facilities reduce the capability of physical modelling. At the same time the wide range of novel hull forms, mooring configurations and materials, and riser types increases the requirement for physical data to calibrate the numerical models and increases the need for design validation. Physical modelling procedures, facilities and limitations are discussed and a design methodology is outlined.

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