Special Issue "Physical Modelling in Hydraulics Engineering"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydraulics".

Deadline for manuscript submissions: 30 May 2020.

Special Issue Editors

Assoc. Prof. Dr. Enrique Peña González
E-Mail Website
Guest Editor
Centre for Technological Innovations in Construction and Civil Engineering (CITEEC), University of A Coruña, Galicia 15001, Spain
Interests: coastal hydraulics; fluvial hydraulics; port operability
Assoc. Prof. Dr. Jose Anta Alvarez
E-Mail Website
Guest Editor
Centre for Technological Innovations in Construction and Civil Engineering (CITEEC), University of A Coruña, Galicia 15001, Spain
Interests: urban hydrology; runoff and wash-off processes; sewer sediments; combined sewer overflows; imaging techniques

Special Issue Information

Dear colleagues,

In recent years, the application of physical modeling in hydraulic engineering has experienced an increasing progress due to several factors, such as (i) the development of new large-scale models, which allows analyzing and simulating different processes in controlled environments under close-to-reality conditions, (ii) the development of new measurement techniques, such as imaging techniques or the application of low-cost technologies, and (iii) a change in the vision of hydraulic engineering that is now more closely connected with other areas of knowledge linked to water quality, ecosystemic services or the social perception of traditional engineering works. These factors, together with other societal challenges such as climate change, population growth or the digitalization of the water sector, have led to a paradigm shift in the development of physical models in the field of hydraulic engineering.

This Special Issue aims to cover the main relevant physical modeling approaches related with hydraulics engineering, including hydraulic structures, fluvial, coastal, transition zones, urban, and ecosystems. All contributions are welcomed, including innovative solutions for common aspects in nature and infrastructures, coming from both basic and applied research. Topics regarding novel instrumentation and application of usual devices to new developments, real case studies, and adaptation to climate change scenarios are especially welcomed. Other topics covered in the Special Issue are nature-based solutions both for environment to urban locations, and studies with comparison with numerical modeling for its calibration, as increasing field of interest. Tentative papers are intended to deeply describe the materials and methods used in the physical modeling, scale effects, and accuracy of the measurements to validate the results.

We await your contributions for this Special Issue of Water, with an attractive impact factor and dissemination worldwide in the scientific community.

Prof. Dr. Enrique Peña González

Assoc. Prof. Dr. Jose Anta Alvarez
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Physical modeling
  • Hydraulic structures
  • Fluvial hydraulics
  • Coastal hydraulics
  • Urban hydrology
  • Ecosystems
  • Innovative facilities and instrumentation

Published Papers (6 papers)

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Research

Open AccessArticle
Mathematical Model of Small-Volume Air Vessel Based on Real Gas Equation
Water 2020, 12(2), 530; https://doi.org/10.3390/w12020530 (registering DOI) - 13 Feb 2020
Abstract
The gas characteristics of an air vessel is one of the key parameters that determines the protective effect on water hammer pressure. Because of the limitation of the ideal gas state equation applied for a small-volume vessel, the Van der Waals (VDW) equation [...] Read more.
The gas characteristics of an air vessel is one of the key parameters that determines the protective effect on water hammer pressure. Because of the limitation of the ideal gas state equation applied for a small-volume vessel, the Van der Waals (VDW) equation and Redlich–Kwong (R–K) equation are proposed to numerically simulate the pressure oscillation. The R–K polytropic equation is derived under the assumption that the volume occupied by the air molecules themselves could be ignored. The effects of cohesion pressure under real gas equations are analyzed by using the method of characteristics under different vessel diameters. The results show that cohesion pressure has a significant effect on the small volume vessel. During the first phase of the transient period, the minimum pressure and water depth calculated by a real gas model are obviously lower than that calculated by an ideal gas model. Because VDW cohesion pressure has a stronger influence on the air vessel pressure compared to R–K air cohesion pressure, the amplitude of head oscillation in the vessel calculated by the R–K equation becomes larger. The numerical results of real gas equations can provide a higher safe-depth margin of the water depth required in the small-volume vessel, resulting in the safe operation of the practical pumping pipeline system. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
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Open AccessArticle
Oblique Wave Attack on Rubble Mound Breakwater Crest Walls of Finite Length
Water 2020, 12(2), 353; https://doi.org/10.3390/w12020353 - 28 Jan 2020
Abstract
Rubble mound breakwaters usually present a crest wall to increase the crest freeboards without a large increase of the consumption of material. Methods in the literature to design crest walls are based on estimates of the wave loads. These methods are focused on [...] Read more.
Rubble mound breakwaters usually present a crest wall to increase the crest freeboards without a large increase of the consumption of material. Methods in the literature to design crest walls are based on estimates of the wave loads. These methods are focused on the maximum loading that attacks a single position of the crest wall. In practice, crest walls have a finite length. Since the maximum loading does not occur at the same instant over the entire length of the crest wall for oblique waves, these methods overestimate the loading in the situation of oblique waves. Wave loads under oblique wave attack have been measured in physical model tests. A method to account for the effect of the finite length of crest walls has been developed, and design guidelines have been derived. The results of this study in combination with the existing methods in the literature to estimate the wave forces enable a more advanced design of crest walls. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
Open AccessArticle
SewerSedFoam: A Model for Free Surface Flow, Sediment Transport, and Deposited Bed Morphology in Sewers
Water 2020, 12(1), 270; https://doi.org/10.3390/w12010270 - 17 Jan 2020
Abstract
This paper aims to bridge the gap in the detailed modelling of flow and sediment process interactions in sewers through the development of a computational fluid dynamics (CFD) model. It draws on previous models developed for surface water sediment transport in the OpenFOAM [...] Read more.
This paper aims to bridge the gap in the detailed modelling of flow and sediment process interactions in sewers through the development of a computational fluid dynamics (CFD) model. It draws on previous models developed for surface water sediment transport in the OpenFOAM CFD framework and builds on them to improve their suitability for sewer sediment processes. Three distinct sediment processes, suspended sediment transport, bedload transport, and deposited bed morphology, are incorporated into a free surface flow solver, interFoam. This sewer sediment model, called SewerSedFoam, models the impacts of sediment deposition and erosion on flow velocity by using dynamic mesh deformation to capture the movement of the deposited bed and its morphology. Further, three sediment classes, two suspended and one bedload sediment, can be modelled along with some bed stabilization and consolidation effects during deposition and erosion, respectively. The functionality of the overall model in modelling sewer sediment deposition and erosion is promising, although the validation of a large magnitude sediment erosion event has been limited by the availability of granular data in existing case studies. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
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Open AccessArticle
The Wall Stress of the Capsule Surface in the Straight Pipe
Water 2020, 12(1), 242; https://doi.org/10.3390/w12010242 - 15 Jan 2020
Abstract
Hydraulic capsule transportation is a new energy-saving transport mode. It is of great significance to the study of flow-field characteristics and pipeline-stress analysis. The purpose of this paper was to analyze the stress distribution on capsule surfaces when there is stationary in pipe [...] Read more.
Hydraulic capsule transportation is a new energy-saving transport mode. It is of great significance to the study of flow-field characteristics and pipeline-stress analysis. The purpose of this paper was to analyze the stress distribution on capsule surfaces when there is stationary in pipe flow. Results showed that the maximum shear stress on the capsule wall appeared in the rear section. Shear-stress range was between 0 and 38 Pa. Principal stress exerted great force on the capsule. The circumferential component of the principal stress was the largest, followed by the axial component, and the radial component was the smallest, i.e., σc > σa> σr. The larger the discharge of pipe flow, the greater the influence of unit discharge on wall shear stress and capsule principal stress, that is, k1 < k2< k3. Under the conditions of this experiment, the axial component of principal stress should include shear stress on the capsule, and Reynolds stress on the capsule cannot be neglected due to water-flow turbulence. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
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Open AccessFeature PaperArticle
Development and Calibration of a New Dripper-Based Rainfall Simulator for Large-Scale Sediment Wash-Off Studies
Water 2020, 12(1), 152; https://doi.org/10.3390/w12010152 - 04 Jan 2020
Abstract
Rainfall simulators are useful tools for controlling the main variables that govern natural rainfall. In this study, a new drop-forming rainfall simulator, which consists of pressure-compensating dripper grids above a horizontal mesh that breaks and distributes raindrops, was developed to be applied in [...] Read more.
Rainfall simulators are useful tools for controlling the main variables that govern natural rainfall. In this study, a new drop-forming rainfall simulator, which consists of pressure-compensating dripper grids above a horizontal mesh that breaks and distributes raindrops, was developed to be applied in wash-off experiments in a large-scale physical model of 36 m2. The mesh typology and size, and its distance to drippers, were established through a calibration where rain uniformity and distributions of raindrop sizes and velocities were compared with local natural rainfall. Finally, the rain properties of the final solution were measured for the three rain intensities that the rainfall simulator is able to generate (30, 50 and 80 mm/h), obtaining almost uniform rainfalls with uniformity coefficients of 81%, 89% and 91%, respectively. This, together with the very suitable raindrop size distribution obtained, and the raindrop velocities of around 87.5% of the terminal velocity for the mean raindrop diameter, makes the proposed solution optimal for wash-off studies, where rain properties are key in the detachment of particles. In addition, the flexibility seen in controlling rain characteristics increases the value of the proposed design in that it is adaptable to a wide range of studies. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
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Open AccessArticle
The Use of a Microscale Physical Model to Simulate Bankfull Discharge in the Lower Reaches of the Yellow River
Water 2020, 12(1), 13; https://doi.org/10.3390/w12010013 - 19 Dec 2019
Abstract
Microscale physical models (MSPMs) were once widely used in flood planning in large basins. They fell out of favor but are now being used again. This paper explores the benefits of using such a model for understanding a flood problem on the Lower [...] Read more.
Microscale physical models (MSPMs) were once widely used in flood planning in large basins. They fell out of favor but are now being used again. This paper explores the benefits of using such a model for understanding a flood problem on the Lower Yellow River (LYR). We constructed an indoor MSPM of a nearly 800-km reach of the LYR. The model had different scales in the longitudinal, transverse, and vertical directions, and we adjusted the slope of the model. Meanwhile, a real-time water level monitoring system and an automatic flow control system were built on the MSPM to automatically control hydrodynamic testing. Through several discharge experiments, bankfull discharge for multiple MSPM sections was obtained and compared with measured data from the corresponding hydrological section of the prototype during the early flood season of 2016. The comparison demonstrated good linear correlation. The analysis of model similarity showed that although there was some deviation in gravity similarity between the MSPM and the prototype, the model discharge scale derived from resistance similarity adequately described the relationship between the model and the prototype bankfull discharge. Further analysis of the relationship between the model and the prototype bankfull discharge revealed that a split-line line may be better than a single regression line. A MSPM could reproduce the bankfull discharge of the LYR with the nearly 800-km reach in the laboratory which is impossible for a small distortion rate physical model, and obtain a result close to that of the assimilated numerical model. Full article
(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Energy Dissipation of Rectangular Free Falling Jets with Downstream Supercritical Flow Conditions
Authors: José M. Carrillo, Francisca Marco, Patricio R. Ortega, Luis G. Castillo and Juan T. García
Affiliation: Universidad Politécnica de Cartagena (UPCT); Paseo Alfonso XIII, 52; 30203 Cartagena, Spain;
Abstract: In recent years, several studies have shown that the current capacity of many spillways may be inadequate, increasing the possibility of overtopping during extreme events. In this situation, new loading scenarios are created in the dams, raising questions about the phenomena of energy dissipation and erosion control at the dam toe. To date, information regarding the behaviour of air-water flows in the plunge pool of free-falling jets is scarce. This study experimentally analyses the flow properties in free falling jet and the supercritical flow after the jet impact. Experiments have been obtained in a 1 m wide experimental device, with a sharp crested weir with the weir crest located at elevation of 2.20 m from the bottom of the plunge pool. Air-water flow properties have been measured in different sections from the weir crest to impact point in the plunge pool. Besides this, the supercritical flow downstream the stagnation point has been also analysed. In the measurements, an intrusive double-tip phase detection probe and a back-flushing Pitot tube have been employed. Several hydrodynamic variables are analysed such as: air concentration (void fraction), bubble frequency, jet velocity, jet thickness and the variation of the solid inner jet core.

Title: Physical modeling study of river discharges and the effects of rotation

Authors: Xiaohui Yan 1,Abdolmajid Mohammadian 2,* , Xin Chen 3

Affiliation: Department of Civil Engineering, University of Ottawa;
Abstract: Pollutants from industrial plants and sewage outfalls are often carried by rivers into large-scale water bodies, and improper control of the transport processes may jeopardize the ecology and environment of the receiving water bodies. Therefore, it is important to better understand the mixing and transport properties of the discharges. The spreading characteristics of small-scale discharges are typically governed by inertia and buoyancy, but the effects of earth’s rotation should not be ignored for large-scale discharges, such as river plumes. To date, information about the effects of rotation on the mixing and transport properties of river discharges is scarce. This study reports physical model experiments of discharges in a rotating system. The experiments were conducted in a rectangular basin, which was hosted on a purposely built rotating table. Various experimental parameters are examined, such as nozzle diameter, initial velocity of discharge, and speed of rotation. The transient spreading processes are recorded, data are extracted using image processing techniques, and mixing and transport characteristics of the discharges are analyzed both qualitatively and quantitatively. The experiments clearly show the effects of source discharge conditions and rotation on the discharges, and provide a comprehensive dataset for development and validation of numerical models.

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