Experimental study for energy dissipation using stilling basin downstream of Piano Key Weirs type A

Author(s):  
Hien Chi ◽  
M Ho
2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Djoko Legono ◽  
Roby Hambali ◽  
Denik Sri Krisnayanti

The utilization of the side channel spillway as the primary component of dam is generally due to the limitation of the available space to construct conventional spillway with design discharge capacity. Some impacts may only be identified through the hydraulic physical model study; these include the presence of the chaotic jumps at the downstream of the spillway crest, the cross flow on the steep channel, as well as the performance of the energy dissipation in the stilling basin. This paper presents the result of the experimental study of three-dimensional behaviour of flow over the entire components of the side channel spillway of Bener Dam, Indonesia. The main dam and its appurtenant components, i.e., the reservoir, the spillway crest, the spillway channel, and the energy dissipaters were built, and various discharges were introduced to study the hydraulic performance of the spillway crest, the stilling basin, the chute, and the energy dissipater. The observed data were collected and then analysed. The results show that firstly, some chaotic hydraulic jumps were found at the stilling basin at downstream spillway crest. These chaotic hydraulic jumps would produce significant vibration that may endanger the nearby structures.  Secondly, the presence of the cross flow along the steep channel downstream of the stilling basin may also need to be eliminated in such that its impact on the rise of water surface level does not create any objection. This may be carried out through the installation of baffles along the spillway channel bed. Thirdly, the presence of the hydraulic jumps at the energy dissipater basin under the design discharge has proven that the energy dissipater has performed well where local scour around the downstream structure was found to be not significant. However, to anticipate the raising of the water surface elevation at the energy dissipater basin, increasing the elevation of energy dissipater wall from +212.50 m to +215.00 m is highly recommended.


1994 ◽  
Vol 30 (6) ◽  
pp. 143-149 ◽  
Author(s):  
H. Deguchi ◽  
M. Kashiwaya

An experimental study was carried out to find a way of using sponge cubes as a biomass support medium to reaction tanks for nitrified liquor recycling process. Type-A, in which biomass fixed cubes are contacted with both anoxic and oxic stages and Type-B, where biomass fixed cubes are contacted with either anoxic or oxic stages, were selected as experimental cases. The results showed that the amount of CO2-C generated which was related to sludge production for Type-B exceeded the amount for Type-A by between 12 to 21%. The nitrification and denitrification rate coefficients at 20°C in Type-A were 1.5 and 1.6 times respectively higher than the coefficients for suspended growth. The rate coefficients in Type-B were 1.5 and 2.0 times respectively higher than the coefficients for Type-A.


Author(s):  
Yong Wang ◽  
Huanjun Jiang ◽  
Chen Wu ◽  
Zihui Xu ◽  
Zhiyuan Qin

<p>Suspended ceiling systems (SCSs) experienced severe damage during strong earthquakes that occurred in recent years. The capacity of the ceiling component is a crucial factor affecting the seismic performance of SCS. Therefore, a series of static tests on suspended ceiling components under monotonic and cyclic loadings were carried out to investigate the seismic performance of the ceiling components. The ceiling components include main tee splices, cross tee latches and peripheral attachments. All specimens were tested under axial loading. Additionally, the static tests of cross tee latches subjected to shear and bending loadings were performed due to their seismic vulnerability. The failure pattern, load-carrying ability, deformation capacity and energy dissipation of the ceiling components are presented in detail in this study.</p>


1987 ◽  
Vol 3 (1) ◽  
pp. 52-56 ◽  
Author(s):  
C. E. Rice ◽  
F. W. Blaisdell

2019 ◽  
Vol 8 (4) ◽  
pp. 2109-2112

Hydraulic jump type II stilling basin is generally preferred as an energy dissipator for ogee spillway but it is uneconomical due to longer structure. On the other hand, roller bucket uses relatively shorter structure over a sloping apron or horizontal stilling basin. In this study, an attempt has been made to evaluate the performance of an ogee profile stepped spillway in combination with solid roller bucket and stilling basin type II for energy dissipation. Laboratory experiments are performed on a physical working model of ogee profile stepped spillway at discharge ranging from 0.0032 to 0.0069 m3 /s for a head of 1.5m, 4m & 7m and the results compared for energy dissipation (non-dimensional parameter (y c / h) = 0.69). The model results show that stepped spillway model without v-notch achieves 92.40 % energy dissipation. Thus this model is found to be more suitable to acquire the ideal condition of sequent depth and tail water depth in stilling basin for all the discharges.


2021 ◽  
Vol 5 (2) ◽  
pp. 155-165
Author(s):  
Bashir Tanimu ◽  
Aliyu Bamaiyi Usman ◽  
Al-Amin Danladi Bello ◽  
Sulaiman Jamilu Abdullahi

This research study the experimental performance of broad-crested weir with single-step by introducing U/S and D/S round-nose and  analysing the parameters that have effect on the shape of the step and their effects on the flow characteristics and energy dissipation (E%) downstream (D/S) of the weir. Furthermore, empirical relations for E% and flow rate due to the influencing factors were derived. The results showed that the weir model with  = 1.000 gives a higher E% in comparison with other weir models. Flow regimes were observed i.e nappe flow for small discharges, transition flow for intermediate discharges and skimming flow for higher discharges. Two model equations were obtained, the first to dteremine the flow rate over the weir models and the second relation to estimate E% in terms of, and Froude number. The model () can be used in the design of prototype weirs in terms of energy dissipation


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