scholarly journals Energy Dissipation of Type a Piano Key Weirs

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1253
Author(s):  
Kam R. Eslinger ◽  
Brian M. Crookston
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Structure ◽  
Type A ◽  
Residual Energy ◽  
Published Data ◽  
Hydraulic Efficiency ◽  
Support Design ◽  
Small Footprint ◽  
Piano Key Weir ◽  
Labyrinth Weirs

A Piano Key weir (PK weir) is a nonlinear, labyrinth-type weir well suited for rehabilitation projects due to a relatively small footprint and the ability to pass large discharges for lesser upstream-head values when compared with other weir types. A critical component of a hydraulic structure is the energy-dissipative properties. Currently, information and guidance is limited, with previous energy dissipation studies of PK weirs primarily of specific projects. Therefore, to document and quantify energy dissipation, four laboratory-scale Type A PK weir models with different width ratios (Wi/Wo) were studied, with 255 tests comprising this new dataset, along with detailed observations of the flow field. Results were compared to existing published data regarding energy dissipation downstream of trapezoidal and rectangular labyrinth weirs. To support design efforts, two equations, both functions of head-water ratio (H/P) and Wi/Wo, are proposed to predict the relative residual energy downstream of PK weirs. The energy dissipation of PK weirs is largest at low flows and decreases in a logarithmic-like manner as flow increases. PK weirs with increased hydraulic efficiency, caused by an increase in Wi/Wo, resulted in slightly smaller energy dissipation values within the range 0.2 ≤ H/P ≤ 0.8. The energy dissipation of PK weirs was found to be relatively constant, independent of Wi/Wo, and in the ranges 0.07 ≤ H/P ≤ 0.2 and 0.8 ≤ H/P ≤ 0.95.

scholarly journals Energy Dissipation and Hydraulics of Flow over Trapezoidal–Triangular Labyrinth Weirs

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1992 ◽  
Author(s):  
Amir Ghaderi ◽  
Rasoul Daneshfaraz ◽  
Mehdi Dasineh ◽  
Silvia Di Francesco
Keyword(s):  
Energy Dissipation ◽  
Discharge Coefficient ◽  
Residual Energy ◽  
Free Flow ◽  
Flow Conditions ◽  
Labyrinth Weir ◽  
Sidewall Angle ◽  
Weir Height ◽  
Downstream Flow ◽  
Labyrinth Weirs

In this work experimental and numerical investigations were carried out to study the influence of the geometric parameters of trapezoidal–triangular labyrinth weirs (TTLW) on the discharge coefficient, energy dissipation, and downstream flow regime, considering two different orientations in labyrinth weir position respective to the reservoir discharge channel. To simulate the free flow surface, the volume of fluid (VOF) method, and the Renormalization Group (RNG) k-ε model turbulence were adopted in the FLOW-3D software. The flow over the labyrinth weir (in both orientations) is simulated as a steady-state flow, and the discharge coefficient is validated with experimental data. The results highlighted that the numerical model shows proper coordination with experimental results and also the discharge coefficient decreases by decreasing the sidewall angle due to the collision of the falling jets for the high value of H/P (H: the hydraulic head, P: the weir height). Hydraulics of flow over TTLW has free flow conditions in low discharge and submerged flow conditions in high discharge. TTLW approximately dissipates the maximum amount of energy due to the collision of nappes in the upstream apexes and to the circulating flow in the pool generated behind the nappes; moreover, an increase in sidewall angle and weir height leads to reduced energy. The energy dissipation of TTLW is largest compared to vertical drop and has the least possible value of residual energy as flow increases.

scholarly journals Hydraulic Advantage of Piano-key Weir Over Ogee Weir

2019 ◽  
Vol 9 (2S2) ◽  
pp. 23-25
Keyword(s):  
Laboratory Investigation ◽  
Hydraulic Structure ◽  
Hydraulic Performance ◽  
Hydraulic Efficiency ◽  
Experiment Data ◽  
Limited Knowledge ◽  
Piano Key Weir

The piano-key weir is a new encouraging hydraulic structure yet to become a widespread usage due to limited knowledge of the hydraulic performance. A laboratory investigation on the hydraulic efficiency of the piano-key weir was compared with that of an ogee weir. The experiment data confirmed that the piano-key weir discharged more than ogee weir for the same upstream head. However, the coefficient discharge of the piano-key weir is extremely low compared to the ogee weir.

Experimental study and numerical simulation of clapboard lead damper

2016 ◽  
Vol 231 (9) ◽  
pp. 1688-1698 ◽  
Author(s):  
SL Cheng ◽  
SY Du ◽  
XS Yan ◽  
Q Guo ◽  
YJ Xin
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Type A ◽  
Loading Test ◽  
Plastic Energy ◽  
Yield Displacement ◽  
Lead Metal ◽  
Reduction Effect ◽  
Hysteretic Properties ◽  
Good Agreement

Two types of clapboard-type lead dampers were designed based on plastic energy absorption of lead metal. The hysteretic curves and energy dissipation properties were studied through low cyclic loading test. Also, the typical restoring load model was extracted. The finite-element numerical model of type-A damper was build according to the characteristics and principle of clapboard-type lead dampers. And the damping effect of high-structural Benchmark model installed with type-A damper was analyzed. The results show that the structure of clapboard-type lead dampers is simple, hysteretic curves are plump, hysteretic properties are steady and yield displacement is small, and thus its energy dissipation ability is excellent. The models of finite element and restoring load of dampers are in good agreement with the results of tests, so they have good applicability. The seismic system installed with type-A dampers has an excellent vibration reduction effect. The top-floor acceleration and displacement control effects are 26.7% and 37.4%, respectively.

Peel Mechanics for an Elastic-Plastic Adherend

1979 ◽  
Vol 52 (5) ◽  
pp. 1057-1071 ◽  
Author(s):  
A. N. Gent ◽  
G. R. Hamed
Keyword(s):  
Energy Dissipation ◽  
Critical Thickness ◽  
Adhesive Layer ◽  
Published Data ◽  
Plastic Yielding ◽  
Plastic Strip ◽  
Elastic Plastic ◽  
Maximum Value ◽  
Good Agreement

Abstract The force required to propagate a 180° bend in an elastic-plastic strip has been calculated from elementary bending theory. Measured forces for Mylar strips of various thicknesses, bent to various degrees, were in good agreement with these calculated values. The corresponding additional stripping force in a peeling experiment will depend upon the thickness of the elastic-plastic adherend, becoming zero both for infinitesimally thin adherends and for those exceeding a critical thickness tc and passing through a maximum value at intermediate thicknesses. Published data are in good agreement with these conclusions. For a strongly adhering strip, higher peel strengths are found for a peel angle of 180°, compared to 90°, and the effect is greater than can be accounted for solely by plastic yielding of the adherend. It is attributed in part to greater energy dissipation within the adhesive layer.

scholarly journals Pharmacoeconomic feasibility of using Mirabegron in patients with overactive bladder

2021 ◽  
Vol 20 (1) ◽  
pp. 35-45
Author(s):  
I. N. Dyakov ◽  
G. R. Kasyan
Keyword(s):  
Botulinum Toxin ◽  
Overactive Bladder ◽  
Economic Analysis ◽  
Impact Analysis ◽  
Pharmacoeconomic Analysis ◽  
Botulinum Toxin Type A ◽  
Type A ◽  
Botulinum Toxin Type ◽  
Published Data ◽  
The Impact

Objective: to assess the clinical and economic efficiency and impact on the budget when using the drug Mirabegron in the treatment of an overactive bladder. Materials and methods. Study design — retrospective analysis of published data. Pharmacoeconomic analysis methods — cost analysis, clinical and economic analysis, budget impact analysis. Results. Despite the fact that the drug Mirabegron for the treatment of overactive bladder is less effective in comparison with the use of the botulinum toxin type A-hemagglutinin complex drug, the clinical and economic analysis showed that within the horizon of 12 months the use of the drug Mirabegron will require 66.8 % less costs. Analysis of the impact on the budget showed that when using the drug Mirabegron from the first year in 100 % of patients, the decrease in the burden on the budget will be 66.8 %. Gradual provision of Mirabegron to patients over 3 years instead of Botulinum toxin type A-hemagglutinin complex will reduce the burden on the budget by 44.4 % in 3 years. Sensitivity analysis showed that the results obtained are resistant to changes in prices for compared drugs and a decrease in the volume of therapy with botulinum toxin type A-hemagglutinin complex. Conclusion. The use of the drug Mirabegron in the treatment of patients with an overactive bladder is pharmacoeconomically justified. The inclusion of Mirabegron in the lists of medicines, the costs of which are subject to state reimbursement, is advisable.

scholarly journals Routing Path Estimation Based on RWS Method for Competent Energy Dissipation Employing X-Layer Network

2019 ◽  
Vol 8 (2) ◽  
pp. 6296-6303
Keyword(s):  
Energy Dissipation ◽  
Error Probability ◽  
Scheduling Algorithm ◽  
Mobile Node ◽  
Residual Energy ◽  
Sensor Nodes ◽  
Idle State ◽  
Proposed Model ◽  
Time Scheduling ◽  
Output Efficiency

In this paper, the implementation of Mobile Error Probability algorithm has been implemented to improve the output efficiency of the sensor nodes in the wireless network environment. According the WSNs is concerned, it’s very important to focus on residual energy of each node. The Mobile Error Probability algorithm support to this very strongly, it ultimately calculates the residual energy corresponding to the consumed energy by the node at each level of the beaconing. This is only applicable for the mobile node depending upon the distance between the nodes. If the distance exceeds the set limit, then only the node sends the beaconing signal else it will be in idle state. Besides, the above concept, the method of RWS is also been implemented to estimate the routing path which can be used for the transmission in minimum stipulated of time. Scheduling algorithm has been used for proper cycling of the node in various modes such as active, idle, sleep and dead conditions. All the above algorithms are been implemented in EQSR, ED as well as proposed model using NS-II simulation through results are also been examined.

scholarly journals Effect of Corner Shape on Hydraulic Performance of One-Cycle Rectangular Labyrinth Weirs

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 117
Author(s):  
Omed S. Q. Yousif ◽  
Moses Karakouzian
Keyword(s):  
Discharge Capacity ◽  
Hydraulic Performance ◽  
Acute Angle ◽  
Effective Length ◽  
Hydraulic Efficiency ◽  
Labyrinth Weir ◽  
Rounded Corner ◽  
Side Walls ◽  
The One ◽  
Labyrinth Weirs

The hydraulic performance of rectangular labyrinth weirs has been investigated by many researchers, however, the effects of the corner shape on the hydraulic performance of rectangular labyrinth weirs have not been addressed in the current literature. Accordingly, this experimental study aims to explore the effect of the corner shape of on discharge efficiency of rectangular labyrinth weirs. Five flat-crested rectangular labyrinth weirs, with five different corner shapes, were made of High-Density Polyethylene Plastic (HDPE) and tested in a rectangular flume. Under different overflow discharges, the discharge coefficients for the rectangular labyrinth weirs were determined. The results showed that the shape of corners for rectangular labyrinth weirs was an effective factor. For example, rounding or beveling the corners can significantly increase the discharge capacity of the rectangular labyrinth weirs. However, the rounded corner shape was slightly better than the beveled corner shape. Among all labyrinth weir models tested in this study, the rectangular labyrinth weir with a semi-circular apex showed the highest hydraulic efficiency, while the one with an acute-angle corner shape showed the lowest hydraulic efficiency. For the rectangular labyrinth weir having a semi-circular shape, although the original effective length reduced by about 14%, the discharge coefficient, CL, increased by 16.7% on average. For the rectangular labyrinth weir that has an acute-angle corner shape, although the effective length (LC) of the weir increased by 23%, its discharge capacity decreased by 35.2% on average. Accordingly, improper folding of the side-walls of the rectangular labyrinth weir led to a significant reduction in the weir’s hydraulic performance.

Energy dissipation by vertically placed screens

2007 ◽  
Vol 34 (4) ◽  
pp. 557-564 ◽  
Author(s):  
Zafer Bozkus ◽  
Pinar Çakir ◽  
A Metin Ger
Keyword(s):  
Energy Dissipation ◽  
Froude Number ◽  
Hydraulic Jump ◽  
Large Range ◽  
Hydraulic Structure ◽  
Flow Depth ◽  
Supercritical Flow ◽  
Series Of Experiments ◽  
Upstream Flow

Screens can be utilized efficiently for dissipating energy of water. In this study, water flowing beneath a gate is used to simulate the flow downstream of a small hydraulic structure, and vertically placed screens are used as an alternative tool for energy dissipation. Investigations are conducted using a series of experiments. The porosity, thickness, and location of the screens are the major parameters together with the Froude number of the upstream flow. The experiments cover a range of supercritical Froude numbers between 5.0 and 18.0, porosities between 20% and 60%, and screen locations up to 100 times the undisturbed upstream flow depth. The thicknesses of the screens used are in the order of the undisturbed upstream flow depth. The results show the importance of each parameter in the energy-dissipating performance of the screens and the system. It is observed that screens dissipate significantly more energy than a conventional hydraulic jump within the large range of Froude numbers covered in the study. The results are also in agreement with the results of an earlier similar study.Key words: screen, energy dissipation, hydraulic jump, porosity, supercritical flow.

Variations des efforts hydrodynamiques sur radiers horizontal et affouillé en aval d'un dissipateur d'énergie de type auge

2007 ◽  
Vol 34 (7) ◽  
pp. 890-894
Author(s):  
A El Amri ◽  
J L Verrette
Keyword(s):  
Energy Dissipation ◽  
Pressure Distribution ◽  
Pressure Fluctuation ◽  
Type A ◽  
Lower Pressure ◽  
Type I ◽  
Reduced Pressure ◽  
Equilibrium Pressure ◽  
Bed Scour ◽  
Stable Flow

The distribution of the hydrodynamic efforts under solid horizontal or scoured bed downstream of a roller bucket spillway can be represented by two typical distributions: type A and B for pressure and type I and II for pressure fluctuation. However, the scoured bed presents a pressure distribution that is closer to the equilibrium pressure compared with that of the horizontal bed and a much lower pressure fluctuation distribution. This could be due to the bed scour in the vicinity of the bucket that carries an effective value for the height of the bucket lip, which decreases the suction effect, and the fact that the eroded shape of the bed corresponds with reduced pressure efforts, which translates into weaker turbulence and therefore a more stable flow. These results show the advantage of a scoured bed that could be more secure when the bucket lip height of the roller bucket spillway is well chosen.Key words: hydrodynamic efforts, pressure, pressure fluctuation, hydraulic energy dissipation, roller bucket.

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