Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Jamel, Asmaa Abdul Jabbar

doi:10.25130/tjes.25.2.03

Cited by 3 publications

(1 citation statement)

References 13 publications

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“…The automated mesh type which consists of tetrahedral elements was built with maximum element numbers of (467600), steady state with RNG k-ϵ turbulence model derived from the Navier stokes equations was selected [19]. The RNG k-ϵ turbulence model predicts more accurate performance for complex flows involving rotation, separation, and recirculation [16,20]. The initial conditions were adopted at the inlet using values of water volume fraction, air volume fraction, and pressure and velocity components.…”

Section: Methodsmentioning

confidence: 99%

Hydraulic Performance for Combined Weir-Gate Structure

Hussein

Jalil

2020

Tikrit j. eng. sci.

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Combined hydraulic structure play an important role in controlling flow in open channels. This study was based on experimental and numerical modeling investigations for combined hydraulic structure. For this purpose three physical models of combined sharp crested trapezoidal weir with bottom opening and one physical model of sharp crested trapezoidal weir separately were used and tested by running eight different flow rates over each model. In which three configurations of bottom opening were tested; the first configuration is a rectangular gate while other two configuration were trapezoidal with two different side slopes of (1V:4H) and (1V:2H). The water surface profiles passing through weir-gate system were measured for all thirty two runs of all models which show uniform flow at 2.11h from the upstream of weir. The commercial computational fluid dynamic software ANSYS CFX was used to simulate flow numerically. The verification of the numerical model was based on water surface profiles and discharge which showed acceptable agreement. Also, the results showed that discharge coefficient Cd varies from (0.52-0.58). Furthermore, it was shown that both models with trapezoidal gate pass a higher discharge of flow than the model with rectangular gate with average percentage increase of discharge (40.78% and 19.40%) for trapezoidal side slopes (1H:2V and 1H:4V) respectively. In addition, the combined system with milder trapezoidal side slopes of bottom opening had a better performance for discharging weir flow which is about 40% as compared with traditional one. Finally, the empirical equations for stage-discharge relationship were estimated for all models and discharge coefficients were estimated for all runs.

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Section: Methodsmentioning

confidence: 99%

Hydraulic Performance for Combined Weir-Gate Structure

Hussein

Jalil

2020

Tikrit j. eng. sci.

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Study the Affecting Factors on Free overfall Flow and Bed Roughness in Semi-Circular Channels by Artificial Neural Network

Irzooki

Najem

2022

Tikrit j. eng. sci.

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One of the significant problems facing the water resource engineer is calculating the coefficient of roughness for subsequent design calculations of the discharge amount of a channel or river. In this study, experiments were conducted in a semi-circular, straight channel to investigate the factors affecting bed roughness and flow discharge using Artificial Neural Network (ANN). For this purpose, three semi-circular channel models with free overfall were constructed and installed in a 6-meter-long laboratory flume. The length of these models was 2.50 m with three different diameters (D= 150, 187, and 237mm) and three bed slopes (S=0.004, 0.008, and 0.012). Three sand particle sizes (ds) were used for each semi-circular channel to roughen the bed. The results showed that the Manning roughness coefficient obtained using a rough bed surface was higher than the channel with a smooth bed surface. Also, the results revealed that the Manning roughness coefficient and the Froude number were inversely related. (ANN) analysis showed a good agreement between the experimental and predicted results of flow and roughness. The bring depth (yb) had an 85.8% impact percentage on the free overfall discharge for semi-circular channels, while the bottom slope (S) had only 1.1%.

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Flow and Energy Dissipation Over a Cylindrical Stepped Weir

Jomaa¹,

Mohammed²

2022

adeletters

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The great economic importance of increasing the energy dissipation flow rate in stepped weirs prompted researchers to make several changes to the geometrical shape. In this study, (36) physical models were constructed to compare cylindrical stepped weirs with traditional weirs. (27) Models of cylindrical stepped weirs and (9) traditional stepped weirs were based on three heights and three diameters of steps. There are three shapes of the weir steps (Fc = all the steps in a circular shape, i.e., without cutting), (Fc & Hc = one round and the other half cut, respectively) and (Hc = all the steps are cut in half). The study showed that the percentage of energy dissipation in weirs increases with the height of the weir (P). Increasing the diameter of the degree (D) and increasing the number of steps (n), and changing the shape of the degrees, as the case (Fc & Hc) was better than the case (Fc). In contrast, the state (Hc) was the best among the other instances in the percentage of flow energy dissipation. The cylindrical gradient weirs are more efficient than traditional stepped weirs by approximately (%10), and the highest value for the energy dissipation of the flow was obtained for stepped cylindrical weirs (%67.27).

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Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Cited by 3 publications

References 13 publications

Hydraulic Performance for Combined Weir-Gate Structure

Hydraulic Performance for Combined Weir-Gate Structure

Study the Affecting Factors on Free overfall Flow and Bed Roughness in Semi-Circular Channels by Artificial Neural Network

Flow and Energy Dissipation Over a Cylindrical Stepped Weir

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