Estimation of scour downstream of a ski-jump bucket using the multivariate adaptive regression splines

Haghiabi, Amir Hamzeh

doi:10.24200/sci.2017.4270

Cited by 15 publications

(6 citation statements)

References 40 publications

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“…Multiple design variables can be subjectively selected for optimization. After the optimization, the size of some flip buckets are hardly able to influence the objective function [29][30][31][32]. is indicates that the height of the flip bucket is related to different arc angles.…”

Section: Discussion Of the Relationship Between The Size Of The Flip mentioning

confidence: 99%

Research on the Optimization Design of Abnormal Flip Buckets

Wang

2020

Mathematical Problems in Engineering

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This study constructs an optimization model to address ski-jump energy dissipation problems in different reservoir environments. The multiobjective genetic algorithm is herein applied as the calculation method. In the process of changing the ski-jump flow model, the runoff of ski-jump flow is changed (especially the abnormal flip bucket). Water flow might go from having a single falling point to multiple falling points. Optimization is only performed after the stabilization of the fall of the water because the fall of the water from the starting point to the ground is not stable over a short period. Only a stable flow can reduce the computation time for optimization. The optimal overflow width and height of the flip bucket were calculated through optimal computation, which can minimize the scouring force of the water flow as it falls to the ground. The results obtained provide theoretical references for practical engineering and reduce the potential safety hazards. The energy in flip buckets following the optimization of the water flow can be fully dissipated, creating an ecosystem where water can flow unobstructed. Guiding a water flow to water-deficient areas is of great significance in ensuring the long-term protection of environments and ecosystems.

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Section: Discussion Of the Relationship Between The Size Of The Flip mentioning

confidence: 99%

Research on the Optimization Design of Abnormal Flip Buckets

Wang

2020

Mathematical Problems in Engineering

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“…Запропоновані параметри пози тіла лижника є інформативними для оцінки ефективності стійки на початку відштовхування юних лижників-стрибунів. Отримані дані доповнюють відомості про ефективність використання методів моделювання в лижному спорті Chardonnens, Favre, Cuendet, Gremion and Aminian (2013), Goyal and Ojha (2011), Haghiabi (2017).…”

Section: дискусіяunclassified

Pattern Recognition: Parameters of Body Inrun Position at the Beginning of Take-Off

Kazmiruk

Banakh

Власов

et al. 2018

Teor. metod. fiz. vihov.

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The purpose of the paper is to determine the differences in the technique of body inrun position at the beginning of take-off in junior ski jumpers of different qualifications (athletic preparedness). Materials and methods. The study participants were 22 junior ski jumpers aged 14-15 (a group of junior ski jumpers) during the Ukrainian Ski Jumping Championship (October 9, 2010, Vorokhta, Ukraine) and 33 ski jumpers aged 16-17 (a group of senior ski jumpers) who took part in the international competitions “Lotos Cup” in January 2010. The study analyzed the videos of take-offs of 22 athletes aged 14-15 and 33 athletes aged 16-17. The parameters of ski jumping technique and sports results were processed on the basis of video materials of the first competition series. Results. There are significant differences (p < 0.001) in the mean values of corresponding parameters of the body position at the beginning of take-off. The data point to a tighter tuck of the body of the athletes aged 16-17. The structure coefficients of the first canonical discriminant function indicate that the function is most significantly related to the values of angles 10 (ν); 8 (ζ); 6 (θ): the inclination angle of the segment of the straight line passing through the axes of the hip and ankle joints (ν) towards the direction of the skier’s movement; the inclination angle of the segment of the straight line passing through the general center of body weight and the axis of the ankle joint (ζ) towards the direction of the skier’s movement; the inclination angle of the head towards the trunk (θ). The athletes aged 16-17 differ from the athletes aged 14-15 by the parameters characterizing the body’s tuck in the starting position – the position at the beginning of take-off. Conclusions. The unstandardized canonical discriminant function coefficients can be used to classify the levels of proficiency in the body’s tuck in the starting position – the position at the beginning of take-off in athletes aged 14-17.

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“…The velocity of the flow on the spillway's chute is very high, which increases the risk of cavitation as well as scouring downstream of the spillway. Spreading downstream scour to the toe of the spillway may damage the dam body (Nou et al 2021;Ghaderi et al 2020b;Haghiabi 2017;Samadi et al 2015). One of the effective ways to dissipate the energy of the flow passing through the spillway's chute is to step its surface (Parsaie and Haghiabi 2019a), which both cause energy dissipation and increase the aeration of the flow (Parsaie and Haghiabi 2019c).…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of flow on circular crested stepped spillway

et al. 2022

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The spillways are one of the most important hydraulic structures used in river engineering, dam construction, irrigation, and drainage engineering projects. Recently, a new type of such spillways with a circular crest has been proposed. In this paper, the hydraulic properties of the circular crested stepped spillway (CCSS) including flow pattern, distribution of velocity on the crest and pressure, turbulence intensity, discharge coefficient ($${C}_{d}$$ C d ) and energy dissipation ratio (EDR) were investigated numerically. To model the free surface of flow the volume of fluid technique, and for modeling the turbulence of flow, k − ε (RNG) was utilized. Results declared that there is a good agreement between the laboratory observations and numerical simulation. The $${C}_{d}$$ C d of the CCSS changes between 0.9 and 1.4 considering the range of relative upstream head ($${h}_{up}/R$$ h up / R ) between 0.33 m and 2.67. The observation of the flow streamlines showed that they are tangential to the curvature of the crest and there is no separation of the flow from the crest. Examination of the pressure distribution on the CCSS model shows that just downstream part of the crest, the pressure is partially negative. Of course, the same partial negative pressure is observed on the edge of the steps. The steps increase the maximum intensity turbulence by 50%. The CCSS can dissipate the energy of flow between 90 and 30%, and in the skimming flow regime, the portion of each step in the energy dissipation regardless of their position is almost identical.

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Estimation of scour downstream of a ski-jump bucket using the multivariate adaptive regression splines

Cited by 15 publications

References 40 publications

Research on the Optimization Design of Abnormal Flip Buckets

Research on the Optimization Design of Abnormal Flip Buckets

Pattern Recognition: Parameters of Body Inrun Position at the Beginning of Take-Off

Numerical simulation of flow on circular crested stepped spillway

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