Sediment Movement over Type A Piano Key Weirs

Kumar, Binit; Kadia, Subhojit; Ahmad, Z.

doi:10.1061/(asce)ir.1943-4774.0001561

Cited by 24 publications

(3 citation statements)

References 48 publications

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“…Denys and Basson (2020) showed that due to the formation of the recirculation zone, the upstream face of the rectangular PKW sidewall experiences significant pressure fluctuations (with an average amplitude of 10% of the total hydrostatic pressure) [37]. According to Kumar et al (2021), a sediment particle accelerates along the inlet key due to the flow contraction and an increase in shear stress [38]. Regardless of the limited ranges of the above-mentioned studies, they imply that the understanding of the complex flow structure (fundamental research) and the analysis of its possible relation to the discharge capacity (applied research) may clarify PKW benefits and limitations.…”

Section: H B B B W a A T C N S S P W P B B W D P R W (3)mentioning

confidence: 99%

Hydrodynamics and Free-Flow Characteristics of Piano Key Weirs with Different Plan Shapes

Sangsefidi

Tavakol-Davani

Ghodsian

et al. 2021

Water

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This paper focuses on Piano Key Weirs (PKWs) as an effective solution for improving the discharge capacity of spillway systems. The flow behavior in inlet and outlet keys is experimentally studied to analyze the discharge capacity of PKWs with different plan shapes (i.e., rectangular, trapezoidal, and triangular). The results show that in outlet keys, the flow aeration regimes extend to higher values of headwater ratios (Ho/P) by increasing the length magnification ratio (B/w) and apex width ratio (A/w). In addition, the local submergence length is a decreasing function of A/w, especially in high flow heads. While the total interference length enlarges by reducing A/w in lower Ho/P values (Ho/P < 0.5), a reverse trend is observed in higher headwater ratios. PKW performance may also be impacted by the flow contraction and recirculation zone in inlet keys, which intensify in higher values of Ho/P, B/w, and A/w. According to the obtained results, while the discharge coefficient is a decreasing function of A/w in Ho/P > 0.4, it may have a reverse trend in lower head conditions. In addition, a trapezoidal PKW has the highest discharge efficiency in a wide range of the studied domain (Ho/P > 0.25 and B/w ≥ 2). It can improve the discharge efficiency by around 5%, while its body volume is almost 7% smaller than the traditional rectangular PKW. However, for low-length and high-head conditions (B/w = 1 and Ho/P > 0.5), the efficiency a rectangular PKW exceeds that of the other shapes.

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Section: H B B B W a A T C N S S P W P B B W D P R W (3)mentioning

confidence: 99%

Hydrodynamics and Free-Flow Characteristics of Piano Key Weirs with Different Plan Shapes

Sangsefidi

Tavakol-Davani

Ghodsian

et al. 2021

Water

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“…Zhao et al (2020) discovered that the saltation height and length increase if the particle shape is not spherical. Moreover, Kumar et al (2021) investigated sediment passage over type-A PKWs and observed that sediment passage at a lesser rate as it goes through the intake key and speeds up at the key entrance. Plunging and impinging jets originating from the inlet and outflow keys were credited with forming the ridge and dip (Kumar & Ahmad 2022).…”

Section: Introductionmentioning

confidence: 99%

Computation of energy dissipation across the type-A piano key weir by using gene expression programming technique

Singh

Kumar

2022

Water Supply

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Energy dissipation across the weir and dam structures is a vital economic and technical solution for designing the downstream morphology of any hydraulic system. Accurately estimating the energy over any hydraulic system using traditional empirical formulas is tedious and challenging. Consequently, employing new and precise techniques still in high demand is crucial. In this study, the authors developed an empirical model for estimating the residual energy downstream of the type-A PKW using gene-expression programming (GEP) by considering six non-dimensional parameters: headwater ratio, magnification ratio, inlet to outlet width ratio, inlet to outlet key bottom slopes, inlet to outlet overhang portions and the number of cycles. The performance of the proposed models has been compared to empirical equations using the statistical factors coefficient of determination (R2), concordance coefficient (CC), and root mean square error (RMSE). The computed relative residual energy values using the proposed models are within ±10% of the observed ones. The proposed GEP model predicted the relative residual energy satisfactorily, with coefficients of determination (R2 = 0.978 for training, 0.980 for testing) and root mean square errors (RMSE) of 0.032, 0.029 for the training and testing datasets, respectively.

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“…Bodaghi et al (2021) experimentally showed that by increasing tailwater depth and discharge, the scour depth downstream of a trapezoidal PKW decreases and increases under free flow conditions, respectively. Kumar et al (2021) investigated the movement of sediment particles on the inlet keys of a rectangular PKW under free-flow conditions. They observed that the speed of the sediment particles decreased by approaching the inlet key.…”

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confidence: 99%

Experimental investigation of scour downstream of a type A trapezoidal piano key weir under free and submerged flow conditions

Bodaghi,

Abdi-Chooplou,

Ghodsian

2024

Journal of Hydrology and Hydromechanics

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In this paper, the scour downstream of a trapezoidal Piano key weir (PKW) is investigated under free and submerged flow conditions. For this purpose, an experimental model was used in a laboratory channel with a length of 10 m, width of 0.75 m, and height of 0.8 m at various discharges and tailwater depths. The results showed an increase and decrease in the maximum scour depth with an increase in the discharge and submergence ratio, respectively. In addition, increasing the particle Froude number enhanced the geometric features of the scour hole downstream of the PKW. The rate of bed changes slowed down over time. The average values of maximum scour depth, the distance of the maximum scour depth from the weir toe, maximum scour hole length and weir toe scour depth increased in the free flow compared to the submerged flow. The scour hole volume and scour hole area in the submerged flow were less compared to the free flow. The average maximum level of the sedimentary ridge in the free flow is less than the submerged flow. New equations for calculating the geometric characteristics of the scour hole downstream of the trapezoidal PKW are presented with acceptable accuracy.

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Sediment Movement over Type A Piano Key Weirs

Cited by 24 publications

References 48 publications

Hydrodynamics and Free-Flow Characteristics of Piano Key Weirs with Different Plan Shapes

Hydrodynamics and Free-Flow Characteristics of Piano Key Weirs with Different Plan Shapes

Computation of energy dissipation across the type-A piano key weir by using gene expression programming technique

Experimental investigation of scour downstream of a type A trapezoidal piano key weir under free and submerged flow conditions

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