Investigation of scours on a physical model of the Hričov weir using photogrammetry

2021 ◽  
Author(s):  
Martin Pavúček ◽  
Ján Rumann ◽  
Peter Dušička
Keyword(s):  
Flow Control ◽  
Physical Model ◽  
Short Range ◽  
Digital Models ◽  
Stilling Basin ◽  
Flood Discharge ◽  
Almost All ◽  
Contactless Measurements

Abstract Scours creation in riverbed at the Hričov weir is a permanent problem since its construction. It is caused by the shortened stilling basin of the weir. In almost all cases of flow control at the weir the energy is not dissipated sufficiently. A 3D physical model was built in the hydraulic laboratory to investigate the measures for reduction of the scour creation. To simulate uneven loads on the downstream riverbed, a flood discharge controlled by the weir in symmetric and asymmetric operations was used for simulations. The scours were evaluated using short-range photogrammetry for contactless measurements. Based on this method digital models of the riverbed for each simulation were created and the scours were assessed to determine the effect of the investigated measures on scour reduction.

ON EVALUATION OF THE ROLE OF THERMAL AND WIND FACTORS FOR A PHYSICAL MODEL OF THE WORLD OCEAN GENERAL CIRCULATION SYSTEM

2019 ◽  
Vol 47 (3) ◽  
pp. 80-91
Author(s):  
V. G. Neiman
Keyword(s):  
Physical Model ◽  
Ocean Circulation ◽  
General Circulation ◽  
World Ocean ◽  
Circulation System ◽  
The Public ◽  
The World ◽  
Almost All ◽  
Conceptual Foundations

The main content of the work consists of certain systematization and addition of longexisting, but eventually deformed and partly lost qualitative ideas about the role of thermal and wind factors that determine the physical mechanism of the World Ocean’s General Circulation System (OGCS). It is noted that the conceptual foundations of the theory of the OGCS in one form or another are contained in the works of many well-known hydrophysicists of the last century, but the aggregate, logically coherent description of the key factors determining the physical model of the OGCS in the public literature is not so easy to find. An attempt is made to clarify and concretize some general ideas about the two key blocks that form the basis of an adequate physical model of the system of oceanic water masses motion in a climatic scale. Attention is drawn to the fact that when analyzing the OGCS it is necessary to take into account not only immediate but also indirect effects of thermal and wind factors on the ocean surface. In conclusion, it is noted that, in the end, by the uneven flow of heat to the surface of the ocean can be explained the nature of both external and almost all internal factors, in one way or another contributing to the excitation of the general, or climatic, ocean circulation.

scholarly journals An Improved Empirical Model for Flood Discharge Atomization and Its Application to Optimize the Flip Bucket of the Nazixia Project

2019 ◽  
Vol 16 (3) ◽  
pp. 316 ◽  
Author(s):  
Jijian Lian ◽  
Junling He ◽  
Fang Liu ◽  
Danjie Ran ◽  
Xiaoqun Wang ◽  
...  
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Empirical Model ◽  
Rainfall Intensity ◽  
Droplet Diameter ◽  
Heavy Rain ◽  
Physical Model Test ◽  
Rain Area ◽  
Left Wall ◽  
Flood Discharge

Flood discharge atomization is a serious challenge that threatens the daily lives of the residents around the dam area as well as the safety of the water conservancy project. This research aims to improve the prediction accuracy of the stochastic splash model. A physical model test with four types of flip bucket is conducted to obtain the hydraulic parameters of the impinging outer edge of the water jet, the relationship of the splashing droplet diameter with its corresponding velocity, and the spatial distribution of the downstream nappe wind. The factors mentioned above are introduced to formulate the empirical model. The rule obtained from the numerical analyses is compared with the results of the physical model test and the prototype observations, which yields a solid agreement. The numerical results indicate that the powerhouse is no longer in the heavy rain area when adopting the flip bucket whose curved surface is attached to the left wall. The rainfall intensity of the powerhouse is significantly weaker than that of other types under the designed condition, so we choose it as the recommended bucket type. Meanwhile, we compare the rainfall intensity distribution of the original bucket and the recommended bucket under different discharge which rates ranging from 150.71 to 1094.9 m3/s. It is found that the powerhouse and the owner camp are no longer in the heavy rain area under all of the working conditions. Finally, it is shown that the atomization influence during the flood discharge can be reduced by using the recommended bucket.

scholarly journals May a Standard VOF Numerical Simulation Adequately Complete Spillway Laboratory Measurements in an Operational Context? The Case of Sa Stria Dam

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1606
Author(s):  
Maria Grazia Badas ◽  
Riccardo Rossi ◽  
Michela Garau
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Numerical Models ◽  
Relevant Information ◽  
Mitigation Measures ◽  
Laboratory Measurements ◽  
Concrete Gravity Dam ◽  
Flood Discharge ◽  
Vof Model ◽  
Under Construction

The present work aims to assess whether a standard numerical simulation (RANS-VOF model with k − ϵ closure) can adequately model experimental measurements obtained in a dam physical model. The investigation is carried out on the Sa Stria Dam, a roller compacted concrete gravity dam currently under construction in Southern Sardinia (Italy). The original project, for which a physical model was simulated, included a downstream secondary dam. However, due to both economic and technical reasons, the secondary dam may not be built. Hence, it is important to assess the flood discharge routing and energy dissipation in the modified plan. Numerical validation is performed adopting the same laboratory configuration, in presence of the downstream dam, and results show a good agreement with mean experimental variables (i.e., pressure, water level). An alternative configuration without the downstream dam is here numerically tested to understand the conditions of flood discharge and assess whether its results can give relevant information for the design of mitigation measures. The topic is of interest also from a more general perspective. Indeed, the feasibility to integrate numerical models with existing laboratory measurements can be very useful not only for new constructions but also for existing dams, which may need either maintenance or upgrading works, such as in case of flood discharge increment.

scholarly journals Experimental Characterization of the Hydraulic Jump Profile and Velocity Distribution in a Stilling Basin Physical Model

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1758
Author(s):  
Juan Macián-Pérez ◽  
Francisco Vallés-Morán ◽  
Santiago Sánchez-Gómez ◽  
Marco De-Rossi-Estrada ◽  
Rafael García-Bartual
Keyword(s):  
Free Surface ◽  
Energy Dissipation ◽  
Velocity Distribution ◽  
Physical Model ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Air Entrainment ◽  
Stilling Basin ◽  
Free Surface Profile ◽  
Stilling Basins

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps.

scholarly journals Analysis of the Flow in a Typified USBR II Stilling Basin through a Numerical and Physical Modeling Approach

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 227 ◽  
Author(s):  
Juan Francisco Macián-Pérez ◽  
Rafael García-Bartual ◽  
Boris Huber ◽  
Arnau Bayon ◽  
Francisco José Vallés-Morán
Keyword(s):  
Physical Model ◽  
Hydraulic Jump ◽  
Numerical Approach ◽  
Free Surface Flows ◽  
United States Bureau ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Modeling Approach ◽  
Stilling Basins ◽  
Energy Dissipation Devices

Adaptation of stilling basins to higher discharges than those considered for their design implies deep knowledge of the flow developed in these structures. To this end, the hydraulic jump occurring in a typified United States Bureau of Reclamation Type II (USBR II) stilling basin was analyzed using a numerical and experimental modeling approach. A reduced-scale physical model to conduct an experimental campaign was built and a numerical computational fluid dynamics (CFD) model was prepared to carry out the corresponding simulations. Both models were able to successfully reproduce the case study in terms of hydraulic jump shape, velocity profiles, and pressure distributions. The analysis revealed not only similarities to the flow in classical hydraulic jumps but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographical information, despite some slight differences. Furthermore, the void fraction distribution was analyzed, showing satisfactory performance of the physical model, although the numerical approach presented some limitations to adequately represent the flow aeration mechanisms, which are discussed herein. Overall, the presented modeling approach can be considered as a useful tool to address the analysis of free surface flows occurring in stilling basins.

CHARACTERISATION OF Al DEFECTS IN SmBa2Cu3-XAlXO6+δ SUPERCONDUCTOR

2003 ◽  
Vol 17 (04n06) ◽  
pp. 936-941 ◽  
Author(s):  
M. SCAVINI ◽  
L. MOLLICA ◽  
R. BIANCHI ◽  
G. A. COSTA ◽  
M. FERRETTI ◽  
...  
Keyword(s):  
Phase Transition ◽  
Short Range ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Orthorhombic Phase ◽  
Superconducting Phase ◽  
Al Doping ◽  
X Ray ◽  
Reducing Conditions ◽  
Almost All

We present here a study on the effect of Al doping on the stucture of SmBa 2 Cu 3-X Al X O 6+δ (Sm-123) superconductor. Electron MicroProbe Analysis (EMPA) and X-Ray Powder Diffraction (XRPD) have revealed that the limit of a aluminium solubility x is between 0.5 and 0.6. For further doping BaAl 2 O 4 appears besides the superconducting phase. XRPD analysis on samples annealed in both oxidising and reducing conditions have revealed that the Al doping inhibits the tetragonal to orthorhombic phase transition. Nuclear Magnetic Resonance (NMR) analysis has shown that almost all the Al ions are coordinated tetrahedrally. The comparison between oxygen non-stoichiometry in pure and Al doped SmBa 2 Cu 3-X Al X O 6+δ suggests that the Al ions are ordered in clusters. A model is proposed for short-range order around Al doping ions which allows us to interpret the phase transition inhibition.

Investigation of stilling basin performance by using physical model and computational fluid dynamics

2017 ◽  
Author(s):  
M. R. Rozainy M. A. Z. ◽  
I. Shafiq ◽  
H. A. Hussein ◽  
M. K. Abdullah ◽  
I. Abustan ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Physical Model ◽  
Stilling Basin

scholarly journals Liposomes Under Real Cell Conditions Behave Like Real Cells with a Single Pulsed Electric Field

2019 ◽  
Author(s):  
Gen Urabe ◽  
Masaharu Shimada ◽  
Takumi Ogata ◽  
Sunao Katsuki
Keyword(s):  
Electric Field ◽  
Red Blood Cells ◽  
Physical Model ◽  
Electric Fields ◽  
Blood Cells ◽  
Pulsed Electric Fields ◽  
Molar Ratio ◽  
Real Cell ◽  
Almost All ◽  
Phosphate Buffered Saline

AbstractLiposomes are widely assumed to present a straightforward physical model of cells. However, almost all previous liposome experiments with pulsed electric fields (PEFs) have been conducted in low-conductivity liquids, a condition that differs significantly from that of cells in medium. Here, we prepared liposomes consisting of soy bean lecithin and cholesterol, at a molar ratio of 1:1, in higher-conductivity liquid that approximated the conditions of red blood cells in phosphate-buffered saline, with inner and outer liquid conductivities of 0.6 and 1.6 S/m, respectively. We found that a single 1.1 kV/cm, 400 μs PEF promoted cell-like spontaneous division of liposomes.

scholarly journals The length of the hydraulic jump on the basis of physical and numerical modeling

2018 ◽  
Vol 50 (1) ◽  
pp. 33-42
Author(s):  
Janusz Urbański ◽  
Piotr Siwicki ◽  
Adam Kiczko ◽  
Adam Kozioł ◽  
Marcin Krukowski
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Computational Fluid Dynamic ◽  
Hydraulic Jump ◽  
Fluid Dynamic ◽  
Sluice Gate ◽  
Ansys Fluent ◽  
Measured Velocity ◽  
Stilling Basin ◽  
Research Goal

Abstract The outcomes of physical and numerical modeling of the sluice gate outflow are presented. The measured velocity distributions in verticals of a physical model were compared with results of numerical modeling, obtained using ANSYS Fluent software. The research goal was verification of suitability of the computational fluid dynamic (CFD) approach in determination of the hydraulic jump length at the outflow of the flow control structure. Studies were performed for the model of the sluice gate and stilling basin with two setups of baffle blocks: in one and two rows. The jump lengths were estimated by an analysis of vertical velocity profiles at the outflow. Two rows of baffle blocks in the stilling basin allowed to reduce the length of the hydraulic jump by 5–10%, comparing to the length with the single row of blocks. The computational fluid dynamic approach underestimated the length of the hydraulic jump by 4–7%, comparing to the physical model.

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