CFD Simulation of Velocity Distribution in a River with a Bend Cross Section and a Cubic Bed Roughness Shape

Majeed, Hayder Q.; Ghazal, Ali M.

doi:10.1088/1757-899x/928/2/022038

Cited by 3 publications

(2 citation statements)

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“…One of the ways to reduce or eliminate the variation of flow velocity in the transvers direction is by increasing the bed roughness close to one side than the other. This prospective study was designed to investigate the use of artificial bed roughness such as cubic and T-section shapes located in one side above the channel bed in the longitudinal direction to increase the manning coefficient in this region and hence reduce the erosion of the bed [3]. Recently, several studies that investigated an artificial bed roughness have been carried out on increasing the manning coefficient in the open channel flow.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, several studies that investigated an artificial bed roughness have been carried out on increasing the manning coefficient in the open channel flow. Most studies in this field have investigated the effect of these roughs on the whole bed surface such as Noori and Saeed [4], Graf and Blanckaert [5], Hendratta et al [6], Ibrahim and Noori [7], Pradhan et al [8], Khoudja and Soudani [9], Yousfi and Aliane [10], and Majeed and Ghazal [3], who conducted a series of CFD simulations with the k-ω SST model were used to calculate Manning's coefficient of artificial geometric roughness element. These elements were placed on the flume's bed and were subjected to various transverse spaces and different angles of attack.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Numerical Study of Open Channel Flow with T-Section Artificial Bed Roughness

Majeed¹,

Ghazal²,

Al-Hadeethi³

2022

MMEP

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Experimental and numerical studies have been conducted on the effects of bed roughness elements such as cubic and T-section elements that are regularly half-channel arrayed on one side of the river on turbulent flow characteristics and bed erosion downstream of the roughness elements. The experimental study has been done for two types of bed roughness elements (cubic and T-section shape) to study the effect of these elements on the velocity profile downstream the elements with respect to different water flow discharges and water depths. A comparison between the cubic and T-section artificial bed roughness showed that the velocity profile downstream the T-section increased in smooth side from the river and decrease in the rough side from it compared with the case when a cubic artificial bed roughness is used. By comparing the results for the element shapes, it can be notices that the T-section bed roughness element more effective compared to cubic shape for both sides of the channel. The numerical method has been done using Computational Fluid Dynamic (CFD) method. A validation for the CFD model with the experimental study have been carried out for a specific flow discharge and water depth. The results indicated that the velocity distribution profiles downstream the bed roughness elements in both sides shown very good agreement for manning coefficients between the numerical and experimental studies. The range of errors between the experimental and numerical study have been calculated using Root Mean Square Error (RMSE) approach, which is found that the RMSE is approximately equal to 1 in case of cubic bed roughness and the RMSE is about 1.5 in case of T-section bed roughness for both smooth and rough sides. Furthermore, the influence of the velocity profile and the bed erosion downstream of the T-section element under the effect of tides have been investigated using the CFD method, which is commonly happened in Shat al-Arab south of Iraq. The results show that the tide of the flow has a reverse effect on the velocity profiles for both sides. Since the velocity profile downstream of bed roughness region increase in the rough side and decrease in the smooth side compared with the normal flow of the river.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Open Channel Flow with T-Section Artificial Bed Roughness

Majeed¹,

Ghazal²,

Al-Hadeethi³

2022

MMEP

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Development and justification of universal designs for energy tests in flow paths of hydroelectric power plants

et al. 2022

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Introduction. The authors present one of methods for measuring water flows through the intake of a hydroelectric power plant. The new structure has a metal frame and a folding rotary row. The authors analyzed the advantages of the proposed, and mase strength and hydraulic analyses. Computational studies of the stress-strain state, made with account taken of the actual hydrodynamic pressure, allow choosing the optimal position of measurement points, designing a frame structure, and making highly accurate measurements of energy characteristics. Materials and methods. Top international publications, as well as archived materials, were analyzed to select the universal frame structure. The most promising directions were identified; the advantages and disadvantages of the proposed solutions were taken into account. Complex computational studies were performed using ANSYS Mechanical, a universal industrial software package, and ANSYS CFX, a specialized module for modeling flows of liquids and gases with account taken of turbulence. Results. The position of measurement points that ensure the least distortion of the flow and tilt angles of hydraulic turntables were determined during the hydraulic simulation. The flow loads were taken into account when the stress-strain state of the universal frame structure was calculated; optimal design solutions were selected to ensure the strength and reliability of metal elements. Stress concentration zones were identified for monitoring purposes during installation. Conclusions. Given the mathematical modeling data and experimental field studies, a universal frame structure for energy tests was substantiated. The new design ensures a measurement error of ±0.67 %, which corresponds to the leading world standards.

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Evaluation of the vibration state and determination of the stress-strain state of the trash-rack structure of the hydroelectric power plants

Antonov,

Karablin,

Baud

et al. 2024

Vestnik MGSU

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изыскательский и научно-исследовательский институт "Гидропроект" им. С.Я. Жука» -«Научно-исследовательский институт энергетических сооружений» (Филиал АО «Институт Гидропроект» -«НИИЭС»); г. Москва, Россия; 2 Национальный исследовательский Московский государственный строительный университет (НИУ МГСУ); г. Москва, Россия АННОТАЦИЯ Введение. Представлен подход по выявлению причины повреждения отдельных ключевых элементов металлоконструкций сороудерживающей решетки (СУР) гидроэлектростанции при техногенных динамических воздействиях. Выполнены прочностные и гидравлические расчеты, а также модальный анализ конструкции. Определен подход и проведены инструментальные измерения фактических динамических характеристик СУР при различных напорах. Материалы и методы. Для выполнения замеров динамических техногенных воздействий разработана методика, состоящая из двух блоков. Первый блок -инструментальное и визуальное обследование для определения соответствия конструкций проектным решениям, а также выявления характерных дефектов СУР. Измерение собственных частот колебаний и виброускорений конструкций при различных напорах выполнялось при помощи пьезоэлектрических вибропреобразователей АР90, измерение виброускорений -сейсмоприемниками А16 и приемной станцией MIC-200. Второй блок -математическое моделирование. Проводилось уточнение гидравлического режима, напряженно-деформированного состояния и определялись частоты и формы собственных колебаний конструкции. Расчетные исследования осуществлены в универсальном промышленном программном комплексе ANSYS Mechanical и ANSYS CFX. Результаты. Обследование выявило наличие систематически возникающих трещин в несущем каркасе, несоответствие положения раскосов проекту. Уточнены гидродинамические нагрузки, определен диаметр и частота образования вихрей. При расчетах напряжения в металлических раскосах не превосходят нормативных величин для используемой стали. Выполненное прямое измерение вибрации элементов конструкции продемонстрировало, что наиболее опасный частотный диапазон -это 40,30-41,75 Гц. Выводы. Установлено, что основной причиной повреждения конструкции СУР является смещение вынужденных частот и формы собственных колебаний в зону работы гидроагрегатов, что и приводило к концентрации напряжений на концах раскосов в зоне примыкания к фасонкам. Стыковка раскосов к фасонке имела недостаточную длину, что приводило к передаче напряжений на край фасонки, и, как следствие, к концентрации напряжений и образованию трещин по направлению главных напряжений в узле.

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CFD Simulation of Velocity Distribution in a River with a Bend Cross Section and a Cubic Bed Roughness Shape

Cited by 3 publications

References 5 publications

Experimental and Numerical Study of Open Channel Flow with T-Section Artificial Bed Roughness

Experimental and Numerical Study of Open Channel Flow with T-Section Artificial Bed Roughness

Development and justification of universal designs for energy tests in flow paths of hydroelectric power plants

Evaluation of the vibration state and determination of the stress-strain state of the trash-rack structure of the hydroelectric power plants

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