Hasil untuk "Hydraulic engineering"

Bo WANG, Fengyin XU, Wenge LIU et al.

Objective and SignificanceAs the coal mining depth increases, coal mining faces increasingly prominent challenges including coal and gas outbursts, rock bursts, and compound dynamic disasters. Deepening the understanding of disaster-causing mechanisms and developing diversified prevention and control technologies are significant for the safe production of coal mines. Employing the key technologies for coalbed methane (CBM) production to control gas-related dynamic disasters is an inevitable course for the safe production of coal mines. However, large-scale, suitable technology systems are yet to be developed. MethodsFrom the perspective of the application of key technologies for surface CBM production, this study systematically reviews the development history and research advances in technologies including well drilling and completion for CBM production and fracturing. From the angle of coal mine safety, this study organizes the disaster-causing mechanisms and critical control technologies for gas dynamic disasters over the past 70 years. In combination with the characteristics of CBM production technologies and the demand for the prevention and control of dynamic disasters in coal mines, this study proposes some suggestions for theoretical innovation and technological breakthroughs. Results and ConclusionsIn terms of theoretical research, it is necessary to deepen the comprehensive exploration of coals and CBM and conduct fine-scale geological studies by integrating multiple approaches. Regarding control technologies, efforts should be made to further explore the control technologies for coal and gas outbursts and rock bursts, with the former including (1) outburst elimination using cavity-type tube wells+high-pressure air/liquid nitrogen/CO2 scrubbing + negative-pressure drainage and (2) multistage fracturing of L-shaped surface horizontal wells+production and the latter including (1) multistage hydraulic fracturing of roofs using L-shaped wells and (2) proppant injection-based multistage hydraulic fracturing for roofs using L-shaped wells+production. Accordingly, advanced technologies such as multistage fracturing of L-shaped wells for CBM production should be employed to conduct on-site experiments on gas dynamic disaster control. It is necessary to explore the applicability of varying prevention and control theories and technologies under different geologic conditions based on scientific research and engineering integrated engineering and projects and develop technology systems for the prevention and control of gas dynamic disasters in coal mines, thus providing robust support for the safe production of coal mines in China.

Ola Mohamed Eraky, A. Ageeb

Planning is the first and most crucial step in problem management and decision-making. Waterway rehabilitation is a widely adopted solution to address the various challenges faced by irrigation canals, such as improving hydraulic efficiency and increasing capacity to meet rising water demands. Uninformed decisions regarding rehabilitation can lead to wasteful expenditure of time, resources, and effort. Therefore, the need for rehabilitation should be guided by a well-defined strategy that identifies hydraulic problems and evaluates the potential impact of rehabilitation measures in addressing these issues. This study aims to develop a strategy to assist decision-makers in assessing the necessity of canal rehabilitation. It proposes a combination of field investigations and numerical modeling to inform decision-making processes. The Suez Waterway in Egypt, an earthen canal, was chosen as a case study. This canal faces significant challenges due to increased sedimentation, which has reduced its flow velocity and discharge capacity. To meet the growing water demands driven by population growth, a need to increase its flow capacity from 3.74 million to 4.53 million cubic meters per day. This study investigates the feasibility of enhancing the hydraulic performance of the canal by modifying its cross-sectional geometry through reshaping and sediment removal, to restore or increase its flow capacity by improving flow velocity and reducing the friction coefficient. In conclusion, this study presents a strategic, data-driven approach for earthen and lined canal rehabilitation decision-making, emphasizing the importance of informed, evidence-based solutions to address hydraulic challenges in irrigation canals. Additionally, it highlights the need to leverage non-traditional water resources to meet future water management demands.

Bowen Zhang, Haojie Liang, Meining Lu et al.

Centrifugal pumps are essential to modern marine engineering systems for fluid transport. This study is to analyze the typical failure causes of sediment erosion and energy dissipation in a multi-stage centrifugal pump with different blade installation angles <i>α</i> using numerical simulation approach and on-site testing. Three different schemes with <i>α</i> = 0°, 10.85°, and 21.7° were designed. The installation angle of the blade influenced sediment erosion and energy dissipation through three key aspects: turbulent flow, particle motion, and wall roughness. Turbulent and friction dissipation, which are related to the blade angle and sediment erosion, are the leading causes of the pump failure. The symmetrical blade installation, turbulence intensity, particle impact velocity, and wall friction inside the unit were the highest, resulting in the most severe turbulence loss, wall loss, and sediment erosion under this scheme, with the maximum friction loss being 320 W·m⁻³·K⁻¹. Complex turbulence intensifies the intensity of particle motion, with the maximum sediment erosion rate <i>E</i> = 0.000052 kg·m⁻²·s⁻¹. Compared to Plan 1 and Plan 3, the performance can be improved by more than 20% and 23%, respectively. There was a positive correlation between the friction loss and erosion rate. The research presented in this study provides a novel perspective on the operation of a pump to prevent sediment erosion failure.

Hassan I. Mohamed, Gamal Abozeid, Nashat A. Ali et al.

Weirs play an important role in controlling and managing water in irrigation canal networks through several functions, such as discharge measurements, water distribution, and lowering the water level. Weirs also play a crucial role in protecting canals from flooding, which might cause the earthen banks to collapse, by eliminating surplus water at the ends of the canals. Over the previous decades, the flow over the traditional sharp-crested weirs was extensively investigated by many researchers; however, the well-escape weirs have not received sufficient attention. These types of weirs were mostly constructed in the form of vertical wells that may be circular or rectangular in shape, and water may flow through the entire perimeter of the weir or part of the perimeter. In the present research, the effect of the well-escape-weir shape on the characteristics of flow over the weir was studied. A set of models were constructed in different shapes, circular and square, and the entire perimeter of the weir or part of the perimeter is working as the weir crest length. The discharge passing over the unit length of the weir crest (q) is investigated and compared for the circular and square weirs of various crest lengths and positions. The results indicated that the discharge capacity of the circular weirs increases by a rate ranging between 7.5% and 15% more than that of the square weirs at the same head. Also, results indicated that the discharge coefficient of the circular weirs increases by a rate ranging between 9.3% and 10.3% more than that of the square weirs. This behavior can be attributed to the interference between the orthogonal water nappes at the corners of the square models. In addition, the flow direction has little effect on the discharge coefficient at small discharges, and this effect becomes more obvious at higher discharges. Additionally, the well-escape weirs of the upstream crest have a slightly higher discharge capacity than those of the downstream crest due to the effect of the approach velocity, which increases the water entrance velocity at the upstream crest. The results of flow patterns around the weir showed that the locations of maximum flow velocities (u, v, w) are mostly near the weir crest and depend entirely on the crest length and position.

Kai Pfennings, Tom K. Hoffmann, Jan Hitzegrad et al.

Abstract Oysters are ecosystem engineering species building reef‐like biogenic structures in temperate shallow water environments, serving as biodiversity hotspots. Recently, also their ecosystem services such as fish nursery, pollutants sink and self‐sustaining coastal protection mechanisms came into a research focus. In light of accelerated sea level rise and increasing environmental dynamics, a determination of vertical growth rates of these biosedimentary structures is paramount in assessing their resilience. This study embarked on a comprehensive survey of seasonal vertical reef growth rates using terrestrial laser scanning and related population dynamics of two intertidal reefs built by the non‐native oyster Magallana gigas in the Wadden Sea. We quantified median reef growth at 19.8 mm yr−1 for the Kaiserbalje reef and 17.5 mm yr−1 for the Nordland reef. Additionally, we tested the hypothesis that the seasonal variations in reef growth rates correspond to the local population dynamics, mainly the parameters of shell length and abundance which mirror delayed effects from previous spawning events. Shell growth rates were 0.03–0.06 mm d−1 in winter and 0.10–0.16 mm d−1 in summer, mean oyster abundance from autumn 2019 to spring 2022 was 627 ± 43 ind. m−2 and 338 ± 87 ind. m−2 at the Kaiserbalje and Nordland reefs respectively. Minor reef growth in the topmost reef area reflects an emerging equilibrium of the vertical reef position to actual sea level. Our findings are in accordance with growth of natural Crassostrea virginica reefs on the US East Coast, indicating potential resilience to actual and predicted sea level rise scenarios. Moreover, understanding local hydro‐morphodynamic feedback linked to sea level rise will be vital in predicting the three‐dimensional stability of these biosedimentary structures and habitats.

Waldemar Treder, Krzysztof Klamkowski, Katarzyna Wójcik et al.

A machine learning model was developed to support irrigation decisions. The field research was conducted on ‘Gala’ apple trees. For each week during the growing seasons (2009–2013), the following parameters were determined: precipitation, evapotranspiration (Penman–Monteith formula), crop (apple) evapotranspiration, climatic water balance, crop (apple) water balance (AWB), cumulative climatic water balance (determined weekly, ΣCWB), cumulative apple water balance (ΣAWB), week number from full bloom, and nominal classification variable: irrigation, no irrigation. Statistical analyses were performed with the use of the WEKA 3.9 application software. The attribute evaluator was performed using Correlation Attribute Eval with the Ranker Search Method. Due to its highest accuracy, the final analyses were performed using the WEKA classifier package with the J48graft algorithm. For each of the analysed growing seasons, different correlations were found between the water balance determined for apple trees and the actual water balance of the soil layer (10–30 cm). The model made correct decisions in 76.7% of the instances when watering was needed and in 87.7% of the instances when watering was not needed. The root of the classification tree was the AWB determined for individual weeks of the growing season. The high places in the tree hierarchy were occupied by the nodes defining the elapsed time of the growing season, the values of ΣCWB and ΣAWB.

LI Ming

Carolina Velásquez, Tricia Wachtendorf

Caribbean islands are particularly vulnerable to extreme events like droughts, co-occurring with groundwater pollution, water inequalities, and weak governance. Consequently, many island communities that rely on tourism are experiencing ongoing and deepening water crises. Technical solutions like desalination are regularly employed throughout the Caribbean, yet water crises persist despite these mitigation strategies. This research focuses on San Andrés, a Colombian Caribbean Island. Following the 2016 water crisis, residents saw the crisis as social: pre-existing social inequalities led to differential water access, quantity, and distribution during the crisis. In contrast, organisational leaders attributed the water crisis to a natural hazard (drought or, more broadly, climate change), even if they recognised disproportional distribution. Interviews revealed strong support from all participants for the use of desalination to address the crisis, despite the inequities that characterise the implementation of this strategy. We argue that San Andrés is moving towards technological water dependence, disconnected from traditional local forms of collecting water and rendering islanders less able to control the resource. We posit that there is a connection between injustice, desalination, and water crises. When a water crisis occurs, it often reveals pre-existing injustices in the social system. Instead of resolving the injustices, desalination, which is often seen as the main solution to the crisis, perpetuates and reinforces them. The result is a cycle of crises that persist over time.

Ruofei Xing, Qin Ju, Slobondan P. Simonoviæ et al.

The Heilongjiang River is a transboundary river between China and Russia, which often experiences ice dams that can trigger spring floods and significant damages in the region. Owing to insufficient data, no river ice model is applicable for the Heilongjiang River. Therefore, a river ice thickness model based on continuous meteorological data and river ice data at the Mohe Station located in the upper reach of the Heilongjiang River was proposed. Specifically, the proposed model was based on physical river ice processes and the Russian empirical theory. System dynamic models were applied to assess the proposed model. The performance of the river ice model was evaluated using root-mean-square error (RMSE), coefficient of determination (R2), and Nash–Sutcliffe efficiency (NSE). Subsequently, sensitivity analyses of the model parameters through Latin hypercube sampling and uncertainty analyses of input variables were conducted. Results show that the formation of ice starts 10 days after the air temperature reaches below 0 °C. The maximum ice thickness occurs 10 days after the atmospheric temperature reaches the minimum. Ice starts to melt after the highest temperature is greater than 0 °C. The R2 of ice thickness in the middle of river (ITMR) and ice thickness at the riverside (ITRS) are 0.67 and 0.69, respectively; the RMSEs of ITMR and ITRS are 6.50 and 6.84, respectively; and the NSEs of ITMR and ITRS are 0.72 and 0.70, respectively. Sensitivity analyses show that ice growth and ice melt are sensitive to the air temperature characterizing the thermal state. Uncertainty analyses show temperature has the greatest effect on river ice. HIGHLIGHTS This study is the first to consider and confirm the lag days between river ice and temperature.; This study builds a river ice model including growth and melt upstream of the Heilongjiang River.; This study is the first to apply system dynamic models to a river ice model.;

Pashupati Nath, P. C. Joshi, Induja Mishra et al.

Dams are playing a significant role in utilizing the resources of water and have a larger impact on the river ecosystem. It has an enormous deal of positive and negative effects on the environment in addition to their benefits like managing stream regimes, as a result preventing floods, obtaining domestic and irrigation water from the stored water and producing energy. The acute and chronic effects due to the construction of the dam are various and categorized according to the area, the services provided by the dams to the community and also its unsocial impacts, advantageous and detrimental impacts on nearby communities and to the aquatic environment These consequences of the construction of any dam project may be commanded in a rigorous and complicated approach resembling climatic, hydraulic, biological, communal, intellectual, archaeological etc. The role of Dams and their benefits are much more and impact directly in our social and environmental life, but it is also a key point that we have to focus about the negative effects of these developmental activities and major and minor dam construction projects by the way of water resource engineering and sustainable development. Dams have the majority of significant functions in utilizing water resources. All through the history of the world, dams have been used successfully in collecting, storing and managing water needed to uphold civilization. Dams have a great deal of affirmative and pessimistic effects on the environment. The advantages are also varying from modest to many folds to the community like controlling stream regime as a result of preventing floods, obtaining domestic and irrigation water from stored water and generating energy from hydropower. Whereas dam endows with significant benefit to our civilization, their impact on the surrounding includes resettlement and relocation, socioeconomic impact, environmental concerns, sedimentation issue, safety aspects etc. Over and above their incredibly important communal and ecological benefits, it is significant to moderate the negative effects of the dam on the environment regarding sustainable development.

Masoud Bahreinimotlagh, Kiyosi Kawanisi, Alireza Kavousi et al.

Fluvial Acoustic Tomography System (FATS) as an advanced technology acquires continuous streamflow data in rivers and estuaries even during floods. However, the acoustic signals are dramatically attenuated by suspending sediments which this problem is a new field of study. In this study, we propose a new equation to estimate the maximum applicable measurement distances (MAMDs). It is based on the cross-sectional suspended sediment concentration (<SSC>) and the particle sizes on the 30-kHz FATS. Our study results show that MAMD might be 2,380 m in the clear water. Moreover, the streamflow monitoring can be perfectly done while <SSC> is less than 12.67 kg/m3 with the particle radii of 3 μm, when the horizontal distance between two acoustic stations is 100 m. Also, the acoustic signals are not decayed if the particle radii equal to 20 mm and the maximum <SSC> is 6.6 kg/m3. This study highlights the performance of FATS in the presence of high <SSC> and provides a better perspective of applying FATS in different rivers with high variability of <SSC>.

CHEN Zishen, ZHAO Lingling, YANG Xing

Taking the maximum 1-hour rainfall (rain peak), maximum 6-hour rainfall and maximum 24-hour rainfall in the Caojiang River Basin from 1967 to 2013 as samples, this paper establishes the typical typhoon rainstorm hydrograph for join trainfall distribution of three periods based on the asymmetric Archimedean Gumbel-Hougaard extreme-value copula. The main conclusions are as follows: (1) The design rainstorm value in Caojiang River Basin calculated through the joint rainfall distribution of three periods is larger than that calculated through the joint rainfall distribution of two periods and a single period. The design rainstorm hydrograph amplified at the same frequency has the optimal overall effect, which provides a new idea for the research of design rainstorm pattern. (2) According to the maximum 24-hour rainfall, the risk rate of the multi-peak rainstorm process with late main peak is the highest, and the typical design rainstorm hydrograp accordingly is the most representative. (3) The design criteria of the joint rainfall of‘OR’ return period with combination of three periods are applicable to the control of rainfall and flood in the river basin.

Songjun Han, Fuqiang Tian

Abstract Szilagyi and Crago criticized our sigmoid generalized complementary function from the boundary conditions and physical limits under the completely wet environments. We believe that their comments originate from different perspectives on the generalized complementary principle. In this reply, we clarify our perspectives, and explain our boundary conditions and physical constraints under the completely wet environments.

Carlos Salazar Briones, Michelle Hallack Alegría, Alejandro Mungaray Moctezuma et al.

Las inundaciones se encuentran entre los peligros naturales más recurrentes y devastadores, al afectar vidas humanas y causar graves daños económicos en todo el mundo. Las regiones áridas y semiáridas son particularmente vulnerables a tormentas intensas en periodos cortos debido a que provocan inundaciones súbitas. Estas regiones representan un 30% del área mundial y están habitadas por 20% de la población. El objetivo principal del presente estudio es estimar la tormenta de diseño para los periodos de retorno de 20, 50, 100 y 500 años en la región semiárida de la subcuenca del Río Nuevo, a fin de determinar las áreas de inundación del cauce principal. Se propone un modelo integrado, que consiste en desarrollar un acoplamiento del modelo hidrológico e hidráulico para diferentes periodos de retorno, alimentados con un Análisis Regional de Frecuencia (ARF), utilizando el enfoque de los L-momentos, empleando los programas HEC-HMS y HEC-RAS. Las áreas de inundación obtenidas de 190.55 a 237.83 ha y profundidades desde 0.10 hasta 6.0 metros comprometen la infraestructura urbana de la ciudad. Los resultados de esta investigación pueden ser utilizados por organismos encargados de la planeación urbana para disminuir riesgos de inundación.

رزا جنوبی, وحید رضاوردی نژاد, فریبرز عباسی

نفوذ، مهمترین و دشوارترین پارامتر در ارزیابی سامانه‌های آبیاری سطحی است. در این مطالعه، به‌منظور برآورد پارامترهای نفوذ معادلة کوستیاکف- لوئیس و ضریب زبری مانینگ در سامانه‌های آبیاری نواری انتهاباز، روش بهینه‌سازی بر اساس معادلة بیلان حجمی توسعه و ارزیابی شد. پارامترهای نفوذ و ضریب زبری با استفاده از داده‌های پیشروی و رواناب برآورد شد. برای اعتبارسنجی روش پیشنهادی، از اطلاعات آزمایش‌های میدانی شش آبیاری نواری استفاده و نتایج با روش‌های دونقطه‌ای و بهینه‌سازی چند سطحی مقایسه شد. بر اساس نتایج، بیشترین دقت در روش بهینه‌سازی چند سطحی با متوسط ریشة میانگین مربعات خطا (RMSE) 7/3 دقیقه را برای زمان پیشروی و درصد خطای نسبی (RE) 5/0 درصد را برای حجم رواناب نشان داد. علاوه‌بر آن، روش پیشنهادی با RMSE برابر 3/5 دقیقه برای زمان پیشروی و RE برابر 7/7 درصد برای حجم رواناب در مرتبة دوم بود. روش دونقطه‌ای با RMSE برابر 8/5 دقیقه برای زمان پیشروی و RE برابر 3/35 درصد برای حجم رواناب پایین‌ترین دقت را نتیجه داد. روش بهینه‌سازی پیشنهادی با دقت نسبتاً خوبی پارامترهای نفوذ و ضریب زبری را برآورد کرد و به‌سهولت همگرا می‌شود و سریع به جواب می‌رسد

Amal Radhi Jubier Alkryishi

The study area is selected in the central plain located between sedimentary latitudes 32°19'30.00" to 33°01'30.00" North and longitudes 43°39'00.00" to 44°52'30.11" East . Alpedonat sites have been identified by the GPS device, and mapped the content of clay soils horizons through studying GIS , as well as of the morphological characteristics mapped after converting them to quantitative attributes ( colour ,structure , consistency) to high clay content maps and this ensures that color appears dark more than the other soil structure of the clay content distributed maps that most construction rule is for the larger , this ratio is back to the type sub angular blocky and is prevalent in soils of arid and semi-arid of the shown the results of agent distribution maps of soil vary in distribution to content of clay , but is higher in clay content. This underlines the importance and the relevance of the content of clay in the soil morphological characteristics and importance in identifying many of the hydraulic and pneumatic relations as well as its importance for agricultural and engineering purposes .

A. A. Kotlobai, A. Ja. Kotlobai, Yu. Sh. Yunusov et al.

Engineering machines being in operational service with military units of  engineer troops are fit to their purpose and their application is relevant in modern conditions. Maintenance of operating conditions in engineering equipment which was produced earlier by the USSR enterprises is considered as a rather complicated task due to lack of spare parts because their production has been discontinued.One of the approaches used for maintenance of engineering equipment combat capabilities is modernization of operating drive systems that presupposes replacement of mechanical systems in working element drives by hydrostatic drives which are realized while using modern element base. Usage of hydraulic units in drive systems being in mass production for replacement of mechanical systems manufactured earlier in small batches makes it possible to reduce labour inputs for maintenance and repair of machines. The paper presents some possibilities for development of operating drive systems in engineering equipment. The proposed approach is given through an example of  engineering obstacle-clearing vehicle (IMR-2M) and excavation machines (MDK-3 and MDK-2M).Application of a hydraulic drive in working elements of the excavation machines permits to withdraw from cardan  shafts, a gear box, a rotary gear and an overload clutch. A hydraulic motor of the cutter and thrower drive is mounted  on a working element gearbox. While executing modernization of hydraulic systems in excavation machines a pump unit has been proposed for the cutter and thrower drive which consists of a controlled pump and a system for automatic maintenance of the pump operational parameters. While developing the operating drive systems in engineering equipment in accordance with the proposed requirements it is possible to simplify drive systems of working elements and  ensure reliable machinery operation in the units of engineer troops.

WANG Meng, LING Chun-hai

José Genivaldo do Vale Moreira, Mauro Naghettini, Julian Cardoso Eleutério

RESUMO A não-estacionariedade em séries temporais hidrológicas tornou-se tema de notória relevância nas últimas décadas. Consequentemente, os métodos convencionais utilizados na análise de frequência e quantificação do risco associado à ocorrência de eventos extremos carecem de adequação. O objetivo do presente trabalho é a análise de frequência e quantificação do risco de precipitação para a duração de dez dias, em Tarauacá, estado do Acre. Os resultados indicaram que a distribuição de Gumbel não-estacionária, com tendência linear temporal nos parâmetros de posição e de escala, conforma-se melhor aos dados observados, permitindo a quantificação mais confiável do risco de eventos raros e a determinação de quantis de referência associados a horizontes típicos de planejamento ou projeto de estruturas hidráulicas.