Estimating Energy Dissipation in Stepped Spillways with Reverse Inclined Steps and End Sill

Hamedi, Amirmasoud; Mansoori, Abbas; Malekmohamadi, Iman; Roshanaei, Hamed

doi:10.1061/41173(414)262

Cited by 10 publications

(5 citation statements)

References 6 publications

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“…Bombardelli et al (2011) compared different turbulence models in FLOW-3D and studied water surface profile, velocity profile and non-aerated region through experimentally measuring and numerically modeling. In addition, the Effects of geometry properties of spillways have been addressed (Hamedi et al, 2011;Attarian et al, 2014;Morovati et al, 2016). Morovati et al (2015) investigated 5 types of configuration of pooled stepped spillway which presented the effects of the configuration of the pools in transverse direction considering standing side wall waves, vortex flow, velocity contours.…”

Section: Introductionmentioning

confidence: 99%

Study of inception point, void fraction and pressure over pooled stepped spillways using Flow-3D

Morovati

Eghbalzadeh

2018

Int Jnl of Num Meth for HFF

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Purpose -While many stepped spillways geometry design guidelines were developed for flat steps, designing pooled steps might be an appropriate alternative to spillways working more efficiency. This paper aims to deal with the inception point of air-entrainment and void fraction in the different height of the pools. Following that, pressure distribution was evaluated in aerated and non-aerated regions under the effect of different heights of the pools and slopes through the use of the FLOW-3D software. Comparison of obtained numerical results with experimental ones was in good agreement for all discharges used in this study. Pools height had the insignificant effect on the inception point location. The value of void fraction was more affected in lower discharges in comparison with higher ones. Negative pressure was not seen over the crest of spillway (non-aerated region), and the maximum pressure values were obtained for pools with 15 cm height along the crest in each discharge. In all slopes, negative pressure was not formed near the step bed in the pooled and flat stepped spillways. However, negative pressure was formed in more area near the vertical face in the flat stepped spillway compared with the pooled stepped spillway which increases the probability of cavitation phenomenon in the flat stepped chute.Design/methodology/approach -A pooled stepped spillway was used in order to evaluate pressure, void fraction, and inception point. Also, different height of the pools was used. Numerical simulation of this study was fulfilled through Flow-3D software. The obtained results indicated that pools can affect two-phase flow characteristics including pressure, void fraction and inception point.Findings -Over the crest, negative pressure was not seen. Pressure values were different for all used heights and the maximum ones obtained for 15 cm height. Also, pooled stepped played a more effective role in reducing the negative pressure points compared with flat cases. Inception point location was more affected in nappe and transition flow regimes in comparison with skimming flow regime particularly for 9 and 15 cm heights.Originality/value -The research results of Felder et al. (2012a) from the University of Queensland were used to numerically simulate the flow over the pooled stepped spillway.

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Section: Introductionmentioning

confidence: 99%

Study of inception point, void fraction and pressure over pooled stepped spillways using Flow-3D

Morovati

Eghbalzadeh

2018

Int Jnl of Num Meth for HFF

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“…Moreover, other works on flow condition, and energy dissipation in stepped spillways equipped with inclined steps or an end sill, have been conducted and the results indicate that inclined steps are reduced more energy than horizontal steps [10][11][12][13]. Among all the investigations conducted on spillways, the research performed by Chaturabul [14] can be singled out.…”

Section: Introductionmentioning

confidence: 99%

Flow Simulation and Energy Loss Estimation in the Nappe Flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Approach

2016

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Recently, the usage of stepped spillways, as energy dissipaters, has increased and led to a reduction in the size of the stilling basin. Extensive experimental considerations, plus the high cost and extended time required for laboratory methods, are among the major issues that require precise attention to determine optimal step design. This research deals with comparing the 2-D numerical simulation and experimental description in stepped spillways equipped with inclined steps and end sill together and presents a brisk, reliable, low-cost, and non-experimental approach to designing the steps. In this new type and complicated geometry, simulation is more complicated than horizontal steps, because it needs more accuracy around the end sills. The VOF Method and the k-ε standard turbulence model are proposed to simulate the flow pattern and evaluate the energy loss over stepped spillway. Energy dissipations obtained through the numerical approach have been compared with laboratory measurements and demonstrate reasonable agreement. Also, the flow pattern, velocity vectors and flow direction resulted from numerical simulation is in a good agreement with the experimental results.

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“…Felder et al did experimental study regarding air-water flow properties and energy dissipation [16], Gonzalez studied on free surface aeration [17], Ohtsu and Yasuda considered characteristics of flow conditions on stepped channels [18], Toomes investigated air-water flow properties on low gradient stepped chutes [19], Zare and Doering worked on inception point of air entrainment and energy dissipation when stepped spillway equipped to baffles and sills [20] [21]. Moreover, other works on flow condition, and energy dissipation in stepped spillways equipped with inclined steps or an end sill, have been conducted and the results indicate that inclined steps are reduced more energy than horizontal steps [22] [23] [24] [25]. Among all the investigations conducted on spillways, the research performed by Chaturabul can be singled out [24].…”

Section: Introductionmentioning

confidence: 99%

Energy Loss Estimation and Flow Simulation in the skimming flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Model

Hamedi¹,

Ketabdar²

2016

IJSEA

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Abstract:Energy dissipaters in dams consider as expensive structures; therefore, economic design of these structure are desirable.Stepped spillways can be use as energy dissipater to reduce the size and cost of the stilling basin. Hard experimental works, high-cost and time-consuming laboratory methods brought about some difficulties to determine the most-efficient design of the steps. This research deals with comparing the two-dimensional numerical simulation and experimental description in stepped spillways equipped with inclined steps and end sill together and presents a quick, trustworthy, economical, and numerical approach to designing the steps. In complicated geometries, simulation is more problematic than simulation of flow in horizontal steps, because it needs more precision around the end sills. Finite volume method and the k-ε standard model are proposed to simulate the flow pattern and evaluate the energy loss over stepped spillway. The flow pattern and velocity vectors resulted from numerical simulation is in a good agreement with the experimental results. Also, energy losses resulted from the numerical approach have been compared with laboratory measurements and demonstrate reasonable agreement.

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Estimating Energy Dissipation in Stepped Spillways with Reverse Inclined Steps and End Sill

Cited by 10 publications

References 6 publications

Study of inception point, void fraction and pressure over pooled stepped spillways using Flow-3D

Study of inception point, void fraction and pressure over pooled stepped spillways using Flow-3D

Flow Simulation and Energy Loss Estimation in the Nappe Flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Approach

Energy Loss Estimation and Flow Simulation in the skimming flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Model

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