scholarly journals Research on the water level in a bending channel using a guide wall

2019 ◽  
Vol 19 (8) ◽  
pp. 2494-2506 ◽  
Author(s):  
Jing Zhang ◽  
Qinghua Zhang ◽  
Tiantian Wang ◽  
Jinmeng Yang ◽  
Xuemei Li
Keyword(s):  
Water Level ◽  
Cross Sections ◽  
Water Surface ◽  
Original Condition ◽  
Bottom Slope ◽  
Channel Bend ◽  
Maximum Value ◽  
Guide Wall ◽  
Maximum Water ◽  
Channel Bottom

Abstract In order to study the water level at the convex and concave banks after installing a guide wall in a spillway chute bend, with the original condition that the Fr at the entrance of the channel bend is larger than 1.0 (supercritical flow) when there is no the guide wall, systematic experiments with the guide wall were conducted for three radii (2.4B, 3.2B and 4B; B is the width of the channel), bottom slopes (0.01, 0.005 and 0.02), and discharges (50, 100 and150 m3 h−1). Results show that, firstly, after installing a guide wall, the Fr becomes smaller and even lower than 1.0, which means the flow status changes from supercritical to subcritical in some conditions with the help of the guide wall. Secondly, the water depth at the convex bank decreases with the increase of the relative axial radius while this presents to be adverse at the concave bank. Thirdly, for water surface differences in cross-sections, the maximum value decreases with the increase of the relative axial radius, and increases with the increase of the discharge per unit width or the bottom slope. Additionally, a novel formula for calculating the maximum water surface difference was obtained in this article.

Experimental study on improvement effect of guide wall to water flow in bend of spillway chute

2015 ◽  
Vol 73 (3) ◽  
pp. 669-678 ◽  
Author(s):  
Qinghua Zhang ◽  
Yanfang Diao ◽  
Xingtao Zhai ◽  
Shuning Li
Keyword(s):  
Water Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Water Surface ◽  
Great Influence ◽  
Flow Rates ◽  
Improvement Effect ◽  
Guide Wall ◽  
The Cross ◽  
Surface Improvement

In order to improve water flow in a bend of a spillway chute using a guide wall, modeling experiments with or without a guide wall under conditions of three different bend axial radii, three chute bottom slopes and three flow rates were carried out in this study. Two indexes were calculated, which are the improved water surface uniformity and the reduced rate of water surface difference in concave and convex banks of the cross-section. The results show that: (1) setting a guide wall in a bend can improve water flow in the bend because it increased the water surface uniformity of the cross-section and reduced the water surface difference in the concave and convex banks; (2) the smaller the bend axial radius, the better the water surface improvement effect will be using a guide wall; (3) the steeper the bottom slope, the more cross-sections with less water surface difference; and (4) flow rates have a great influence on water surface improvement in the bend, and the guide wall can improve water flow obviously when the water depth in the starting section of the bend is lower than the height of the guide wall. This study has important implications in engineering design of guide walls.

scholarly journals Effects of the bottom slope and guiding wall length on the performance of a vortex drop inlet

2018 ◽  
Vol 78 (6) ◽  
pp. 1287-1295 ◽  
Author(s):  
Dong Sop Rhee ◽  
Yong Sung Park ◽  
Inhwan Park
Keyword(s):  
Water Surface ◽  
Laboratory Experiments ◽  
Surface Elevation ◽  
Design Criteria ◽  
Bottom Slope ◽  
Flow Conditions ◽  
Water Surface Elevation ◽  
Approach Channel ◽  
Maximum Water ◽  
Intake Structure

Abstract Laboratory experiments were conducted to assess the performance of a vortex drop inlet with a spiral intake in subcritical and supercritical flow conditions. The water surface elevation at multiple locations was measured for different flowrates by varying the extent of the guiding wall and the longitudinal and radial bottom slopes. The measurements show that a steeper longitudinal bottom slope decreases the water surface elevation at the beginning of the intake, resulting in a transcritical flow in the intake structure. However, a steeper longitudinal bottom slope also causes the maximum water surface elevation to occur within the spiral intake. For an effective vortex drop inlet design, achieving a low water surface elevation throughout the entire spiral intake structure is required. Experimental results show that the two seemingly conflicting design criteria, namely, achieving a low water surface elevation in the approach channel and reducing the maximum water surface elevation in the intake structure, can be simultaneously achieved by adding a radial bottom slope.

Evaporation and Viscous Flow in Triangular Grooves in Micro Heat Pipes

2005 ◽  
Author(s):  
Mulugeta Markos ◽  
Vladimir S. Ajaev ◽  
G. M. Homsy
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Cross Sections ◽  
Wedge Angle ◽  
Heat Pipes ◽  
Type Model ◽  
Pressure Gradients ◽  
Maximum Value ◽  
Dry Out ◽  
Micro Heat Pipes

We develop a lubrication type model of a liquid flow in a wedge in the limit of small capillary numbers and negligible gravity. The model incorporates the effects of capillary pressure gradients and evaporation. Steady vapor-liquid interface shapes are found for a range of parameters. In the limit of weak evaporation the flow is the same in all cross-sections and can be controlled by changing the wedge angle. We find the wedge angle that results in the maximum value of the flow rate for a given contact angle. For high evaporation rates, both the flow rate and the amount of liquid in each cross-section along the wedge decrease until the point of dry-out is reached. The location of the dry-out point is studied as a function of evaporation. Practical suggestions about optimization of micro heat pipes are given.

Denoising of river surface photogrammetric DEMs using deep learning

2021 ◽  
Author(s):  
Radosław Szostak ◽  
Przemysław Wachniew ◽  
Mirosław Zimnoch ◽  
Paweł Ćwiąkała ◽  
Edyta Puniach ◽  
...  
Keyword(s):  
Higher Education ◽  
Deep Learning ◽  
Water Level ◽  
Water Surface ◽  
Research University ◽  
Static Characteristic ◽  
Water Levels ◽  
Training Dataset ◽  
Observation Data ◽  
Characteristic Points

<p>Unmanned Aerial Vehicles (UAVs) can be an excellent tool for environmental measurements due to their ability to reach inaccessible places and fast data acquisition over large areas. In particular drones may have a potential application in hydrology, as they can be used to create photogrammetric digital elevation models (DEM) of the terrain allowing to obtain high resolution spatial distribution of water level in the river to be fed into hydrological models. Nevertheless, photogrammetric algorithms generate distortions on the DEM at the water bodies. This is due to light penetration below the water surface and the lack of static characteristic points on water surface that can be distinguished by the photogrammetric algorithm. The correction of these disturbances could be achieved by applying deep learning methods. For this purpose, it is necessary to build a training dataset containing DEMs before and after water surfaces denoising. A method has been developed to prepare such a dataset. It is divided into several stages. In the first step a photogrammetric surveys and geodetic water level measurements are performed. The second one includes generation of DEMs and orthomosaics using photogrammetric software. Finally in the last one the interpolation of the measured water levels is done to obtain a plane of the water surface and apply it to the DEMs to correct the distortion. The resulting dataset was used to train deep learning model based on convolutional neural networks. The proposed method has been validated on observation data representing part of Kocinka river catchment located in the central Poland.</p><p>This research has been partly supported by the Ministry of Science and Higher Education Project “Initiative for Excellence – Research University” and Ministry of Science and Higher Education subsidy, project no. 16.16.220.842-B02 / 16.16.150.545.</p>

ON DISTRTBUTION PATTERN OF AMORPHA FRUTICOSA L. IN THE REGION OF KANEVSKAYA HYDROPOWER STATION (UKRAINE) IN CONNECTION WITH HYDROCHORY

2021 ◽  
Vol 14 (1) ◽  
pp. 107-115
Author(s):  
T. V. Shevchik ◽  
T. S. Dvirna ◽  
V. L. Shevchik
Keyword(s):  
Water Surface ◽  
Water Yield ◽  
Surface Level ◽  
Amorpha Fruticosa ◽  
Active Dispersal ◽  
Active Dissemination ◽  
Maximum Water ◽  
Hydropower Stations ◽  
Determining Factor ◽  
Natural Way

Amorpha fruticosa L. is a kenophyte of North American origin, ergaziophyte. Currently, this species naturalized over large areas and became the background on the coast waters of the Dnieper reservoirs of hydropower stations. It is necessary to clarify the reasons for the distribution of A. fruticosa populations in different parts of the Middle Dnieper coast under conditions of artificial regulation of its water yield. It has been proven that the high buoyancy of A. fruticosa fruits provides the possibility of its active dispersal along river beds in a natural way under conditions of fluctuations in the level of surface water yield right in spring floods. The main and determining factor in the active dissemination of the species on the coast of the Kanev and Kremenchug reservoirs is the frequent variability of the maximum water surface level. The narrow altitudinal range of distribution of this species on the coast in the lower parts, and accordingly, wider in the upper parts of the reservoirs is determined by the corresponding indicators of water level differences. The possibility of artificial regulation of the water surface level with knowledge of the characteristics of hydrochory of this invasive species makes it possible to influence its distribution in the territory near the reservoirs.

3D modelling of the flow distribution in the delta of Lake Øyeren, Norway

2010 ◽  
Vol 41 (2) ◽  
pp. 92-103 ◽  
Author(s):  
Peggy Zinke ◽  
Nils Reidar Bøe Olsen ◽  
Jim Bogen ◽  
Nils Rüther
Keyword(s):  
Water Level ◽  
Cross Sections ◽  
Stokes Equations ◽  
Morphological Changes ◽  
Flow Distribution ◽  
Field Measurements ◽  
Navier Stokes ◽  
Error Sources ◽  
Navier Stokes Equations ◽  
Water Level Measurements

A 3D numerical model was used to compute the discharge distribution in the channel branches of Lake Øyeren's delta in Norway. The model solved the Navier–Stokes equations with the k–ɛ turbulence model on a 3D unstructured grid. The bathymetry dataset for the modelling had to be combined from different data sources. The results for three different flow situations in 1996 and 1997 showed a relative accuracy of the computed discharges within the range of 0 to±20% compared with field measurements taken by an ADCP at 13 cross sections of the distributary channels. The factors introducing the most error in the computed results are believed to be uncertainties concerning the bathymetry. A comparison between the computational results of the older morphology data from 1985–1990 and the model morphology from 1995–2004 indicated that morphological changes in this period had already had consequences for the flow distribution in some channels. Other important error sources were the inevitable use of averaged water level gradients because of unavailable water level measurements within the delta.

scholarly journals Failure of Zoned Earth Dam (An analysis of earth dam break)

2019 ◽  
Vol 27 (1) ◽  
pp. 344-353
Author(s):  
Abdul-Hassan K. Al-Shukur ◽  
Ranya Badea’ Mahmoud
Keyword(s):  
Water Level ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Water Flux ◽  
Dam Break ◽  
The Body ◽  
Earth Dam ◽  
Dam Failure ◽  
Maximum Water Level ◽  
Maximum Water

One of the most common type of embankment dam failure is the dam-break due to overtopping. In this study, the finite elements method has been used to analyze seepage and limit equilibrium method to study stability of the body of an earthfill dam during the flood condition. For this purpose, the software Geostudio 2012 is used through its subprograms SEEP/W and SLOPE/W. Al-Adhaim dam in Iraq has been chosen to analysis the 5 days of flood. It was found that the water flux of seepage during the flood reaches about 8.772*10-5. m3/sec when the water level 146.5 m at 2nd day. Seepage through the embankment at maximum water level increased by 55.1 % from maximum water level. It was concluded that the factor of safety against sliding in downstream side decrease with increasing water level and vice versa. It was also concluded that the deposits are getting more critical stability during the conditions of flood when the factor of safety value reaches 1.219 at 2nd day.

scholarly journals Surface Heat Budget estimation for Laurance Lake, US

2021 ◽  
Vol 877 (1) ◽  
pp. 012005
Author(s):  
Dahlia S. Abed-Zaid ◽  
Hussein A. M. Al-Zubaidi
Keyword(s):  
Surface Temperature ◽  
Water Surface ◽  
Heat Budget ◽  
Meteorological Data ◽  
Longwave Radiation ◽  
Atmospheric Conditions ◽  
Large Lakes ◽  
Water Surface Temperature ◽  
Maximum Water ◽  
The Many

Abstract Estimating heat budget factors are important to understand the many physical processes of large lakes and their reaction to the atmosphere. Some of these components are affected by water temperature, while the other depends on atmospheric conditions. This paper estimates the total heat flux for Lawrence lake via a code developed in MATLAB environment. The code can deal with different time resolutions if the lake water surface temperature data were at different time resolutions from the meteorological data. Results showed that solar energy peaks at 842 Watt/m2 at 540 Julian day, which is very normal for a sunny summer day, while the longwave radiation has 204 Watt/m2 as a min value. The back radiation did not make any reaction for the variation, but it revealed a small gradient. Furthermore, evaporation recorded - 67 Watt/m2 as a minimum value at 659 Julian day and 360 Watt/m2 as a maximum value at 578.43 Julian day close to the maximum water surface temperature event.

scholarly journals Effect of Water Management Practices on Rice Yield, Water Productivity and Water Savings under Irrigated Rice Paddy Ecosystem

2017 ◽  
Vol 9 (2) ◽  
pp. 79-84 ◽  
Author(s):  
SC Barman ◽  
MA Ali ◽  
HJ Hiya ◽  
KR Sarker ◽  
MA Sattar
Keyword(s):  
Water Management ◽  
Water Level ◽  
Management Practices ◽  
Rice Yield ◽  
Water Productivity ◽  
Ground Level ◽  
Productivity Index ◽  
Water Savings ◽  
Maximum Water ◽  
Irrigation Treatments

A field experiment was carried out during the Boro season 2013 to find out the effects of water management practices on rice yield performance and water productivity index at Old Brahmaputra flood plain paddy land, Muktagacha, Mymensingh. The experiment was laid out in randomized complete block design (RCBD) with six (6) irrigation treatments. Two treatments, T1 and T3 were kept under continuous standing water levels (10 cm and 5 cm respectively) while in treatment T5 irrigation water was supplied for 1st 3 weeks then followed mid season drain out and re-flooded at flowering stage. Three alternate wetting and drying irrigation treatments, T2, T4 and T6 were selected in which irrigation water was applied when water level dropped 20cm, 10cm and 15cm below ground level, respectively. All the irrigation treatments significantly affected the rice yield and yield contributing parameters. The study revealed that the highest grain yield (5950 kg ha-1) was found in treatment T5 which was identical with AWDI treatment T4 (5820 kg ha-1) followed by AWDI treatment T6 (5460 kg ha-1). On the contrary, rice yield of 3350 kg ha-1, 4470 kg ha-1 and 4810 kg ha-1 were found in the treatment T1, T2 and T3, respectively. It was found that AWDI treatment T2 showed maximum water savings (15.1%) followed by T6 (11.3%), T4 (7.59%) and T5 (3.8%), however rice yield in the treatment T2 (4470 kg ha-1) was significantly lower compared to T6, T4 and T5 treatment. Therefore, it may be inferred that treatment T4 (AWDI; irrigation when water level fell 10 cm from ground level), T5 (Irrigation for 1st 3 weeks, then mid-season drain out and re-flooding at flowering) and T6 (AWDI; irrigation when water level fell 15cm from ground level) would be the feasible choice for the water savings, higher rice yield as well as maximum water productivity index (0.478, 0.472 and 0.467, respectively) for sustaining rice farming during the dry Boro season in Bangladesh.J. Environ. Sci. & Natural Resources, 9(2): 79-84 2016

scholarly journals Study of the Optical Properties of Functionalized Gold Nanoparticles in Different Tissues and Their Correlation with the Temperature Increase

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
A. Carrillo-Cazares ◽  
N. P. Jiménez-Mancilla ◽  
M. A. Luna-Gutiérrez ◽  
K. Isaac-Olivé ◽  
M. A. Camacho-López
Keyword(s):  
Cross Sections ◽  
Temperature Increase ◽  
Mie Theory ◽  
Average Temperature ◽  
Theoretical Maximum ◽  
Maximum Value ◽  
Homogeneous Media ◽  
532 Nm ◽  
Different Tissues ◽  
Functionalized Aunps

Mie theory explains the interaction of light with a gold nanoparticle (AuNP) through the absorption (Cabs), scattering (Csca), and extinction (Cext) cross sections. These parameters have been calculated in the case of AuNPs dispersed in homogeneous media, but not for specific tissues. The aim of this research was to theoretically obtain the optical cross sections (Cabs, Csca, and Cext) of functionalized AuNPs in liver and colon tissues through Mie theory and correlate them with the temperature increase observed experimentally in tissues containing AuNPs under plasmonic photothermal irradiation using a Nd-YAG laser (λ = 532 nm). Calculations showed that Cabs represents 98.96±0.03% of Cext at 532 nm. The Cext value for a functionalized AuNP in water was 365.66 nm2 (94% of the theoretical maximum value at 522.5 nm), 404.24 nm2 in colon (98% of the theoretical maximum value at 525 nm), and 442.39 nm2 in liver (96% of the theoretical maximum value at 525 nm). Therefore, nanoparticles irradiated at 532 nm are very close to their resonance value. These results correlated with the experimental irradiation of functionalized AuNPs in different tissues, where the average temperature increase showed the pattern liver > colon > water. The temperature increase observed (ΔT up to 13°C) is sufficient to produce cellular death.

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