Effects of Gate Lip Orientation on Bottom Pressure Coefficient of Dam Tunnel Gate

Taher, Taha M.; Anwar, Awat O.

doi:10.1007/s13369-016-2202-7

Cited by 9 publications

(5 citation statements)

References 5 publications

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“…Their results showed that K b values are relatively between 0.25 and 0.45 at low Y/Y o , and then all were reduced and converge to lower values as Y=Y o increases. These results are clearly different from those obtained from the current study which already based upon a constant flow rate of Q ¼ 0:035 m 3 =s ð Þ , which has a significant effect on behavior and values of (K b ), and this value is mostly different from that used by Taher [11]. Such difference in results of K b seems possible and expected and may be attributed to their different experimental conditions.…”

Section: Distribution Of Bottom Pressure Coefficient (K B )contrasting

confidence: 99%

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Variation of Pressure Coefficient Along Bottom of Dam Vertical Lift Gates

Ahmed

2020

J. Inst. Eng. India Ser. A

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The vertical lift gates are exposed to hydrodynamic forces that arise as a result of pressurized flow established by the large-scale effect of the water levels in the dam reservoirs. The most influential forces are those that are applied on the gate vertically upward due to the intensity of the flow under the gate and downward as a result of passage flow above the gate. The difference between these two forces generates a downpull force that is the most important gate stability indicator. In this research, an arbitrary hydraulic model was constructed to investigate the effects of many gate lip shapes with and without extensions on the magnitudes and distribution of bottom pressure coefficient when the values of flow and shaft gap width ratio (b 2 /b l) are constant. The results indicate that the bottom pressure coefficient appears to vary uniformly with gate openings and seem to be influenced effectively by the gate lip geometry. So, for the given value of (b 2 /b l), the top pressure coefficient regarding the downward force will mostly be with uniform changes and hence the downpull coefficient depends on the magnitudes and distribution of bottom pressure coefficient. An attempt by using the correlation coefficient of Statistical Package of Social Sciences was made to determine whether the pressure fluctuation is significantly shown at the bottom pressure distribution curve, which in turn is considered as appropriate indicator for the vibration occurrence. Full range of maximum bottom pressure coefficients in a matrix form is made to assist in design purposes. The results are analyzed and many conclusions are obtained.

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Section: Distribution Of Bottom Pressure Coefficient (K B )contrasting

confidence: 99%

“…Similar work by using only the cases of ordinary gate lips of (h = 45°and h = 55°) has been conducted by Taher [11]. Their results showed that K b values are relatively between 0.25 and 0.45 at low Y/Y o , and then all were reduced and converge to lower values as Y=Y o increases.…”

Section: Distribution Of Bottom Pressure Coefficient (K B )mentioning

confidence: 59%

Variation of Pressure Coefficient Along Bottom of Dam Vertical Lift Gates

Ahmed

2020

J. Inst. Eng. India Ser. A

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“…In the mentioned destructive phenomena, parameters such as flow rate, velocity, water's hydrodynamic pressure, air velocity entering the flow, and water depth are effective. By measuring some of these parameters, they can be prevented from happening before failure [34]. Furthermore, due to the governing equations' nature, it is essential to start the flow analysis with fixed boundary conditions so that eventually the flow reaches a steady state after a suitable time in the model.…”

Section: Evaluation Of Numerical Modeling Results With Flow-3dmentioning

confidence: 99%

Hydrodynamic Performance and Cavitation Analysis in Bottom Outlets of Dam Using CFD Modelling

Yamini

Mousavi

Kavianpour

et al. 2021

Advances in Civil Engineering

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Bottom outlets are significant structures of dams, which are responsible for controlling the flow rate, operation, or removal of reservoir sedimentation. The service gate controls the outlet flow rate, and whenever this gate is out of order, the emergency gate which is located at upstream is utilized. The cavitation phenomenon is one of the common bottom outlets’ problems due to the rapid flow transfer. The present research is a numerical study of the flow pattern in a dam’s bottom outlet for different gate openings by the use of Flow-3D software and RNG k-ε turbulence model. The investigation is carried out on the Sardab Dam, an earth dam in Isfahan (Iran). The maximum velocity for 100% opening of the gate and Howell Bunger valve is about 18 m/s in the section below the gate, and the maximum velocity for 40% opening of the gate is equal to 23.1 m/s. For 50% opening of the service and emergency gate in the valve’s upstream areas, the desired pressure values are reduced. Moreover, in the areas between the two emergency and service gates, the pressure values are reduced. The possibility of cavitation in this area can be reduced by installing aerators. The flow pattern in Sardab Dam’s bottom outlet has relatively stable and proper conditions, and there are no troublesome hydraulic phenomena such as local vortices, undesirable variations in pressure, and velocity in the tunnel, and there is no flow separation in the critical area of flow entering into the branch.

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“…Taher et al [17] used a random hydraulic model to study the effects of twelve gate lips orientation on the behaviour of flow and consequently on the bottom pressure coefficient. The main conclusion indicates that the values of bottom pressure coefficient (K b ) are inversely proportional to gate opening ratios (Y/Y 0 ) and range from high values with small gate openings ratios and low values for (Y/ Y 0 [ 30%).…”

Section: Introductionmentioning

confidence: 99%

Effects of Geometrical and Flow Rates on the Prediction of Bottom Pressure Coefficients of Tunnel Lift Gate of Dams

Ameen

Taher²,

Ahmed

2018

J. Inst. Eng. India Ser. A

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Hydrostatics and hydrodynamics forces are generated and applied on the vertical lift tunnel gates due to the influence of a wide range of dam operating conditions. One of the most important forces is the uplift force resulting from the jet flow issuing below the gate. This force is based mainly upon many hydraulic and geometrical parameters. In this work, the uplift force is studied in terms of bottom pressure coefficient. The investigation is made paying particular attention on the effects of various three discharges and three gate lip angles on values of bottom pressure coefficients in addition to four different tunnel longitudinal slopes whose impact has not been studied in many previous works. Hydraulic model is constructed in this work for the sake of measuring all parameters required for estimating the bottom pressure coefficients, which are all examined against gate openings. The results show that the bottom pressure coefficient is related to the said variables, however, its behaviour and values are not necessary regular with variance of studied variables. The values are seen more significantly related to the flow rates and for some extent to the slopes of tunnel. An attempt by using the nonlinear regression of Statistical package of social sciences (SPSS) is made to set equations relating bottom pressure coefficient with gate openings for several angles of gate lips. The obtained equations are shown in good agreement with the selected cases of experimental results. The results are applicable for design purposes for similar geometrical and flow parameters considered in this study.

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Effects of Gate Lip Orientation on Bottom Pressure Coefficient of Dam Tunnel Gate

Cited by 9 publications

References 5 publications

Variation of Pressure Coefficient Along Bottom of Dam Vertical Lift Gates

Variation of Pressure Coefficient Along Bottom of Dam Vertical Lift Gates

Hydrodynamic Performance and Cavitation Analysis in Bottom Outlets of Dam Using CFD Modelling

Effects of Geometrical and Flow Rates on the Prediction of Bottom Pressure Coefficients of Tunnel Lift Gate of Dams

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