The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Abdelazim M Negm - One of the best experts on this subject based on the ideXlab platform.
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effect of supercritical flow on scour characteristics downstream of sudden expanding Stilling Basins
International Journal of Engineering, 2016Co-Authors: Abdelazim M Negm, G M Abdelaal, Osama K Saleh, M F SauidaAbstract:The effect of different expansion ratios of sudden expanding Stilling Basins (SESB) on scour characteristics of dov/nstream (DS) movable soil is investigated in this paper. The flow tlirough sudden expansion is supercritical in the approaching channel witli imder-gate Froude number ranging from 1.25 to about 5. Tliree expansions ratios (2.0, 2.5 and 3.0) are considered. The experiments are conducted in a laboratory flume 30 cm wide, 3.5 m Long, and 0.25 m deep. The widtli of the approach channel is kept unchanged. The collected infomnation are analyzed in tenns of the maximum scour depth relative to the gate opening. Botli tlie effects of Froude number and channel expansions are discussed. Different flow and scour patterns are presented and discussed. A prediction equation is developed to compute tlie deptli ratio'in tenns of the under-gate Froude niunber, the expansion ratio and tlie relative gate opening. Good agreement is-obtained between the predicted and the measured values using an independent set of experimental data.
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minimization of scour depth downstream radial Stilling Basins
2007Co-Authors: Abdelazim M NegmAbstract:In this research paper, the effect of the position of central symmetric sill on the maximum scour depth downstream (DS) of radial Stilling basin (RSB) was investigated experimentally. Central symmetric sill of particular length (normal to the flow direction) were tested at different positions with reference to the position of the control gate. The flow pattern was observed and the scour pattern was measured for each test. The optimal position of the central symmetric sill that minimizes the maximum depth of scour DS. radial Stilling basin based on the analysis of the experimental measurements. Results were compared to the no sill case. It was obtained that the scour is minimized if the sill is installed within the middle third of the basin. The effect of using an end sill combined with the central sill at the optimal position was also investigated. It was found that the scour process were slightly reduced (in each of the three dimensions) when the central sill at the optimal position was combined with the end sill. A prediction model was developed using the multiple linear regression analysis to estimate the maximum scour depth. The other characteristics of the scour and deposition process were also presented and discussed.
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effect of end sill on scour characteristics downstream of sudden expanding Stilling Basins
2004Co-Authors: Abdelazim M Negm, Noha G AhmadAbstract:Scour downstream of a hydraulic structure may endanger the whole structure after long or short run depending upon the extent of scouring processes. It is highly recommended to prevent the downstream bed from being scoured if possible or minimize the dimensions of the scour hole and force it to form away from the end of the Stilling basin to increase the safety of the structure. It is believed that the end sill when carefully designed- can have an important role to force the scour hole and reduce the extent of erosion. In this paper, the effects of using end sills in the sudden expanding Stilling Basins are addressed experimentally. Stilling Basins with different expansion ratios of 1.54, 2.0 and 2.5 are used to collect the scour information when a sill is installed at the end of the basin. Sills of different dimensions are tested under wide range of flow conditions. The optimal sill that reduces the extent of scour downstream of the most practical sudden expanding Stilling basin is recommended.
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effect of asymmetric side sill on scour characteristics downstream of sudden expanding Stilling Basins
2004Co-Authors: Osama K Saleh, Abdelazim M Negm, Noha G AhmadAbstract:Previous investigations proved that Scour downstream of Sudden Expanding Stilling Basins (SESB) are asymmetric due to the asymmetric flow conditions in the basin. Improving the flow pattern inside the basin by forcing it to be symmetric will improve the resulting scour pattern downstream of the basin. Different measures may be used to improve the flow pattern in the sudden expanding Stilling basin. One of these measures is using one or more asymmetric side sill at certain position with particular orientation. In this paper, the effect of asymmetric side sill on the scour characteristics represented by the maximum scour depth downstream of SESB is investigated. Determination of the best position of the asymmetric side sill is the main objective of the present research. The effects of such conditions on the flow patterns inside the Basins are also discussed. It is concluded that using asymmetric side sill reduces the maximum scour depth significantly, especially when two asymmetric side sills are used. A simple prediction equation is developed for estimating the maximum depth of scour knowing the Froude number or the upstream head ratio and the relative position of the sill.
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effect of sill arrangement on maximum scour depth downstream of abruptly enlarged Stilling Basins
2004Co-Authors: Abdelazim M NegmAbstract:Scour downstream (DS) of hydraulic structures (HS) may endanger the safety of the structures if the necessary precuations are not considered during the design stage. Normally, different measures produce different effects on reducing the maximum scour depth DS of HS. One of the important HSs is the abruptly enlarged (or sudden expanding) Stilling Basins. In this paper, the effects of different arrangements of sills inside an abruptly enlarged Stilling basin will be discussed. An experimental program was conducted to investigate the effects of continuous end sill, one asymmetric side side, double staggered asymmetric side sills, symmetric side sills, central sill and continuous central sill. The flow patterns were observed and the maximum scour depths were recorded. The results revealed that in most of the cases the flow patterns are asymmetric resulting in asymmetric scours. The reduction in the maximum scour depth depends on the type of arrangement of the used sill and on the flow conditions represented by Froude number. Both of the central sill with limited width and continuous central sill improved the flow patterns towards symmetric type and yielded minimized maaximum scour depth with preference to the continuous sill.
Arun Goel - One of the best experts on this subject based on the ideXlab platform.
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Stilling Basins below outlet works an overview
2010Co-Authors: H L Tiwari, Arun Goel, Maulana AzadAbstract:A Stilling Basins are transition structures constructed to dissipate excess energy confined by high velocity flow at the outlet of conduit or tunnel so that the flow beyond the basin does not endanger the stability of bed and banks of downstream channel. In a Stilling basin kinetic energy causes turbulences and it is ultimately lost as heat and sound energy. there are several types of Stilling Basins which are used in various hydraulic structures like dam, canal, culvert etc. The type of Stilling basin most suitable at a particular location mainly depends upon initial Froude Number and initial velocity of flow. This paper covers design principles and features of various Stilling Basins used for outlet works.
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experiments on Stilling Basins for dam outlets
Proceedings of the Institution of Civil Engineers - Water Management, 2007Co-Authors: Arun GoelAbstract:A series of experiments was performed with the aim of developing shorter and more efficient Stilling Basins for dam outlets (in comparison with Garde's Stilling basin), keeping the floor of the basin at the invert level (lowest level of outlet) of the outlet. The experiments were conducted for a pipe outlet diameter d = 58 mm, inflow Froude number Fr = 3·44 and basin lengths of 12d, 10d, 8d and 7d. New models were developed by conducting systematic experimentation on Stilling basin models using different types of appurtenances such as wedge-shaped blocks, a grid, an intermediate sill and an end step. It was found that the newly developed Stilling basin models are not only shorter in length but also show superior performance in terms of maximum depth of scour and its location when compared to Garde's model.
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experimental study on Stilling Basins for square outlets
2007Co-Authors: Arun GoelAbstract:This paper proposes new shorter and efficient designs by means of laboratory experimentation as compared to USBR type VI Stilling basin models. The models are tested on 4cm x 4cm square opening (d = 4cm) for Froude number (Fr) = 6.83 with a diverging side walls at a slope of 1V:0.8 H. Appurtenances of several shapes and sizes like splitter block, impact wall, baffle blocks, intermediate sill, and end sills are tested in the laboratory at different locations. It has been found that a row of wedge shaped block quite is helpful in spreading the jet of water in a shorter length of basin with diverging side walls, resulting into better and more energy dissipation. It was found that the length of Stilling basin models can be reduced (12.9d to 10.9d) i.e. by more than 15% as compared to USBR impact type VI Stilling basin model.
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alternate designs of Stilling Basins for pipe outlets
Irrigation and Drainage Systems, 2006Co-Authors: Arun Goel, D V S VermaAbstract:An experimental work leading to the development of economical and improved Stilling basin designs for circular pipe outlet in comparison to Garde's Stilling basin [Garde, R.J. & Saraf, P.D., Journal of Irrigation and Power 1986, 145–154], is reported in this paper. In the present study, attempts are made to develop efficient and shorter Stilling basin models keeping the basin floor at the invert level of the pipe outlet for inflow Froude number Fr = 5.50. The new designs are arrived at by conducting a systematic experiments on the Stilling basin models having appurtenances like a wedge-shaped splitter block, a modified grid, an intermediate sill and a rounded step. Scour index, a non-dimensional number has been defined to compare the performance of the Stilling basin models using the same erodible material and time of experimental run. The performance of the newly developed Stilling basin models has been compared with that of Garde's Stilling basin model G-D∗. The proposed model M is also compared with the earlier Stilling basin model M-12, as suggested by Goel & Verma [Journal of Irrigation and Drainage Systems 15(1), 2001, 81–91].
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new Stilling Basins designs for deep rectangular outlets
International journal of engineering. Transactions A: basics, 2004Co-Authors: D V S Verma, Arun GoelAbstract:The experimental study reported here is intended to evolve new designs of Stilling Basins for deep and narrow openings used as outlets. Several appurtenances such as grid, Impact wall, stepped wall, weir wall, sloping end sill and wedge shaped blocks are used to study their influence on the hydraulic performance of the Stilling Basins with an aim to propose efficient Stilling basin models. All the models were tested at inflow Froude number Fr = 4.89 keeping a constant run time and same erodible bed material for each Stilling basin model for comparison of the performance. The performance of each model was evaluated by observing the maximum depth of scour and its location after the end sill. A non-dimensional number named as Scour Index has been evolved for comparing the performance of the different Stilling basin models. The use of wedge shaped blocks as a splitter block and baffle blocks reduced the depth of scour indicating a significant dissipation of energy and good flow conditions, downstream of the Stilling basin.
G M Abdelaal - One of the best experts on this subject based on the ideXlab platform.
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effect of supercritical flow on scour characteristics downstream of sudden expanding Stilling Basins
International Journal of Engineering, 2016Co-Authors: Abdelazim M Negm, G M Abdelaal, Osama K Saleh, M F SauidaAbstract:The effect of different expansion ratios of sudden expanding Stilling Basins (SESB) on scour characteristics of dov/nstream (DS) movable soil is investigated in this paper. The flow tlirough sudden expansion is supercritical in the approaching channel witli imder-gate Froude number ranging from 1.25 to about 5. Tliree expansions ratios (2.0, 2.5 and 3.0) are considered. The experiments are conducted in a laboratory flume 30 cm wide, 3.5 m Long, and 0.25 m deep. The widtli of the approach channel is kept unchanged. The collected infomnation are analyzed in tenns of the maximum scour depth relative to the gate opening. Botli tlie effects of Froude number and channel expansions are discussed. Different flow and scour patterns are presented and discussed. A prediction equation is developed to compute tlie deptli ratio'in tenns of the under-gate Froude niunber, the expansion ratio and tlie relative gate opening. Good agreement is-obtained between the predicted and the measured values using an independent set of experimental data.
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theoretical modeling of hydraulic jumps at negative step in radial Stilling Basins with end sill
2003Co-Authors: G M Abdelaal, Abdelazim M NegmAbstract:The hydraulic jump has been studied as an important method for energy dissipation downstream water structures. Several methods have been used to optimize the hydraulic jump length. One of the common methods was the use of end sill. Steps may be used to control the location of the hydraulic jump downstream of hydraulic structures. Extensive studies have been conducted to investigate the effect of steps in rectangular Basins but not yet in radial Basins. In the present paper, theoretical models are developed to predict the depth ratios of the radial hydraulic jumps at negative steps downstream of the control structures when the Stilling Basins is ended with a sill. Both the momentum and continuity equations in one dimension are applied to the control volume where the jump begins and ends. Both forms of the hydraulic jump (A and B) at negative step in the radial Stilling Basins are dealt. An experimental program is conducted to collect experimental data to enable verification of the developed theoretical models. Good agreement between theoretical and experimental results is obtained. The developed models are recommended for use in the design of radial Stilling basin to compute the depth ratios which is needed to complete the dimensioning of the Stilling basin.
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investigation of b jump negative step in radial Stilling Basins
2003Co-Authors: Abdelazim M Negm, G M AbdelaalAbstract:Presence of steps in radial Stilling Basins affect positively or negatively the characteristics of the free hydraulic jumps depending upon the type of the step, the height of the step, the position of the step in the basin and the dominant flow conditions. The effects of all these factors on the characteristics of the free radial hydraulic B-jump are addressed through the present experimental investigation. It is found that the depth ratio and the length of jump ratio increase by the increase of the relative step height while the energy loss is decreased. A theoretical model for the computation of the energy loss is developed. Also, statistical models are proposed for predicting the characteristics of the formed free hydraulic B-jump at the negative step in the radial Stilling basin. The experimental results are compared with the theoretical ones for energy loss and with the staistical ones for the length of jump. Good agreements are obtained between the results of the developed models and the experimental ones.
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theoretical modeling of hydraulic jumps in radial Stilling Basins ended with sills
2003Co-Authors: A A Habib, Abdelazim M Negm, G M Abdelaal, T M OwaisAbstract:The use of end sill is one of the common methods that have been used to optimize the hydraulic jump length. Extensive studies have been conducted to investigate the effect sills or end sills on the hydraulic jumps in rectangular Basins but not yet in radial Basins. The complete design of Stilling Basins needs the accurate estimation of the depth ratio of the formed hydraulic jump in the basin. In the present paper, a theoretical model is developed to predict the depth ratio of the radial hydraulic jump when a basin is ended with a sill. Both the momentum and continuity equation in one dimension are applied to the control volume where the basin begins and ends. Also, the energy equation is used to develop a theoretical model to evaluate the energy loss by the radial hydraulic jump when a sill exists at the end of the basin. An experimental program is conducted to collect experimental data to enable verification of the developed theoretical models. Good agreement between theoretical and experimental results is obtained. The developed models could be used safely to compute both the depth ratio of the jump and the energy loss by the jump formed in radial basin with an end sill.
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hydraulic characteristics of submerged flow in non prismatic Stilling Basins
2002Co-Authors: Abdelazim M Negm, G M Abdelaal, M I Elfiky, Abdalla MohamedAbstract:Careful and economic design of Stilling Basins is a major factor when considering design of hydraulic structures such as barrages, weir, spillways, ..., etc. Recently, the non-prismatic Stilling Basins attracted many researchers due to its effective dissipation of excess energy. Radial Stilling Basins are characterizing with symmetric flow patterns that in turn minimize the expected damages of the erodible bed downstream the Stilling Basins. In this paper, the submerged flow in radial Stilling basin provided with negative step and an end sill is analyzed both theoretically and experimentally. The effects of various parameters such as submergence, relative height of sill, relative height of step and inlet Froude number are presented and discussed. The experimental study is conducted on 30 cm wide, 45 cm deep and 12 m long open channel. The theoretical study utilizes the onedimensional momentum and continuity equations. The developed equations are verified using the obtained experimental data. Also, prediction models to estimate the length of jump are developed using the dimensional analysis and statistical methods. The models are calibrated and verified using the experimental data.
Javad Farhoudi - One of the best experts on this subject based on the ideXlab platform.
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local scour profiles downstream of adverse Stilling Basins
Scientia Iranica, 2015Co-Authors: Khalili H Shayan, Javad FarhoudiAbstract:In this paper, scour profiles downstream of adverse Stilling Basins due to the submerged jet issuing from a sluice gate, were investigated. Experiments were conducted in a wide range of sediment sizes, incoming flow Froude numbers, tailwater depths, length and slope of Stilling basin. The results showed that the scour profiles at any bed slope are similar in shape. However, the longitude evolution of scour profiles and the volume of eroded materials were increasing in accordance with slope of basin. It was observed that the maximum depth of scour hole occur at the vicinity of side walls and slightly decrease towards the centerline. A polynomial equation was derived to describe the nondimensional scour profiles at different slopes. Based on experimental data, the scour characteristics have been correlated with the time of equilibrium stage by developing some empirical relationships. Finally, a power-law equation was derived and fully defined to include the dimensions of scour hole time scale and geometry of sluice gate.
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investigation on local scour downstream of adverse Stilling Basins
Ain Shams Engineering Journal, 2014Co-Authors: Javad Farhoudi, Hossein Khalili ShayanAbstract:Abstract This paper is focused on local scour downstream of adverse Stilling Basins where a submerged wall jet issued from a sluice gate. Experiments were conducted in a wide range of Froude numbers, grain sizes, tailwater depths, and Stilling basin slopes. The results showed that the scour profiles at any bed slope follow shape similarity. However, the longitude evolution of scour profiles and the volume of eroded materials were increasing in accordance with slope of basin. A polynomial equation was derived to define the non-dimensional profiles under different slopes. The time evolution of scour hole dimensions and the equilibrium state were defined. It was found that under a specific condition of sediment grain size, approaching Froude number, the length and slope of adverse basin, the scour depth at the downstream of adverse basin, initially increases with tailwater depth, and after reaching its maximum value decreases to a constant value. It was also observed that the maximum depth of scour hole was decreased as the length and slope of Stilling basin increased, whereas the longitudinal dimensions of the hole were increased. It was found that the maximum depth of scour hole occurs at the vicinity of side walls with slight decrease in the centerline. Finally, a power equation was expressed to fully define the dimensions of scour hole, time scale and geometry of sluice gate.
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application of neuro fuzzy model to estimate the characteristics of local scour downstream of Stilling Basins
Journal of Hydroinformatics, 2010Co-Authors: Javad Farhoudi, Seiyed Mossa Hosseini, Mohammad SedghiaslAbstract:The local scour phenomenon in the vicinity of bridge piers and Stilling Basins has received considerable attraction from designers due to its consequences which may endanger these structures. Various factors govern the pattern of scour evolution which results in the complexity of this phenomenon. Many researchers indicated that the use of fuzzy logic in modeling this phenomenon could be a promising alternative to reflect the vagueness and ambiguity of effective parameters. The aim of this study is to investigate the performance of a neuro-fuzzy model based on Takagi and Sugeno's theory in estimating the maximum depths, pattern and time evolution of scour hole downstream of a Stilling basin of U.S.B.R. type I. The investigation was conducted under various discharges, tail-water depths (low, balanced and high), different bed materials and model sizes. The characteristics of the equilibrium state of the scour phenomenon as well as the time to reach the maximum scour depth were considered. The results showed a significant conformity between estimated and experimental data which recommends an acceptable outcome using a neuro-fuzzy model to forecast the properties of scour hole downstream of Stilling Basins. This would contribute to predicting the design geometry of Stilling pools and taking the appropriate precautions to protect the downstream channel bed.
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pressure fluctuation around chute blocks of saf Stilling Basins
Journal of Agricultural Science and Technology, 2010Co-Authors: Javad Farhoudi, S M Sadathelbar, Najdat I AzizAbstract:Geometry of the chute blocks in Stilling Basins plays a significant role in size and type of these structures. One of the most influencing factors in the design of the blocks is the fluctuating pressure which may cause fatigue on the blocks. Despite investigations conducted by many researchers, there is not enough information about the pressure fluctuation around chute blocks in compacted Stilling Basins such as Saint Anthony Falls (SAF) Basins. In this paper, the results of a naval experimental work and measurement of pressure fluctuations around chute blocks of SAF Stilling Basins are reported. The results show that the pressure fluctuations around the chute blocks cannot be overlooked in designing such structures. The variation of pressure fluctuation with Froude number of incoming supercritical flow at various faces of the chute block is reported, which shows an increasing trend of pressure fluctuation. It is also observed that the submergence of hydraulic jump will decreasingly affect the pressure fluctuations. The trend of variations will follow different patterns at the different faces of the block.
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total pressure around chute blocks of saf Stilling Basins
International Journal of Civil Engineering, 2009Co-Authors: Javad FarhoudiAbstract:Induced total pressure by flow, including mean and fluctuating components, around a selected chute block in SAF Stilling Basins downstream of an ogee spillway was studied. Several pressure holes were selected on various faces of a selected chute block to get enough information regarding the total pressure field. This paper reports the results of an experimental work and measurement of mean and fluctuation pressures around chute blocks of SAF Stilling Basins. The observations showed that the maximum total pressure varies inversely with Froude number of incoming flow while its position of occurrence follows a quadratic polynomial relationship. Statistical analysis also showed that the peak instantaneous pressure fluctuations could be as large as ±4.5times the RMS value.It is concluded that pressure fluctuation around the chute blocks may double the magnitude of pressure field around the chute blocks and can not be overlooked in designing such appurtenances.
D V S Verma - One of the best experts on this subject based on the ideXlab platform.
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alternate designs of Stilling Basins for pipe outlets
Irrigation and Drainage Systems, 2006Co-Authors: Arun Goel, D V S VermaAbstract:An experimental work leading to the development of economical and improved Stilling basin designs for circular pipe outlet in comparison to Garde's Stilling basin [Garde, R.J. & Saraf, P.D., Journal of Irrigation and Power 1986, 145–154], is reported in this paper. In the present study, attempts are made to develop efficient and shorter Stilling basin models keeping the basin floor at the invert level of the pipe outlet for inflow Froude number Fr = 5.50. The new designs are arrived at by conducting a systematic experiments on the Stilling basin models having appurtenances like a wedge-shaped splitter block, a modified grid, an intermediate sill and a rounded step. Scour index, a non-dimensional number has been defined to compare the performance of the Stilling basin models using the same erodible material and time of experimental run. The performance of the newly developed Stilling basin models has been compared with that of Garde's Stilling basin model G-D∗. The proposed model M is also compared with the earlier Stilling basin model M-12, as suggested by Goel & Verma [Journal of Irrigation and Drainage Systems 15(1), 2001, 81–91].
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new Stilling Basins designs for deep rectangular outlets
International journal of engineering. Transactions A: basics, 2004Co-Authors: D V S Verma, Arun GoelAbstract:The experimental study reported here is intended to evolve new designs of Stilling Basins for deep and narrow openings used as outlets. Several appurtenances such as grid, Impact wall, stepped wall, weir wall, sloping end sill and wedge shaped blocks are used to study their influence on the hydraulic performance of the Stilling Basins with an aim to propose efficient Stilling basin models. All the models were tested at inflow Froude number Fr = 4.89 keeping a constant run time and same erodible bed material for each Stilling basin model for comparison of the performance. The performance of each model was evaluated by observing the maximum depth of scour and its location after the end sill. A non-dimensional number named as Scour Index has been evolved for comparing the performance of the different Stilling basin models. The use of wedge shaped blocks as a splitter block and baffle blocks reduced the depth of scour indicating a significant dissipation of energy and good flow conditions, downstream of the Stilling basin.
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development of efficient Stilling Basins for pipe outlets
Journal of Irrigation and Drainage Engineering-asce, 2003Co-Authors: D V S Verma, Arun GoelAbstract:The results of experimental work leading to the development of shorter and improved Stilling Basins for pipe outlets are reported. The original USBR impact type VI Stilling basin incorporates a floor that is depressed below the invert elevation of the pipe outlet. In the present study, efforts are made to develop an efficient Stilling basin keeping the floor at the invert elevation of the pipe outlet. Experiments were conducted for two pipe diameters with Froude numbers ranging from 1.70 to 5.50. The new models were developed by conducting systematic experiments on a large number of Stilling Basins with different configurations of the appurtenances such as the splitter block, impact wall, baffle blocks, and end sill in terms of their shapes, sizes, and locations. A performance number has been defined to compare the performances of various Stilling Basins using a constant experimental running time and same erodible material for each model. The shapes and sizes of various appurtenances and corresponding performance results are presented. The performance of the newly developed efficient and economical Stilling Basins are compared with the performance of the USBR impact type VI Stilling Basins for pipe outlets within the range of the Froude numbers tested.
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studies on Stilling Basins with diverging side walls
Water and Energy International, 2003Co-Authors: D V S Verma, Arun Goel, B SinghAbstract:This paper presents an experimental work leading to the evolvement 01 efficient Stilling basin models having diverging side walls. The experiments on various Stilling basin geometries were conducted at Froude numbers (Fr) = 4.17 and 6.15. It was found that the performance of Stilling Basins with diverging side walls having a play of 1:3 can be improved by adding appurtenances like baffle hlocks, end sill or by providing a reverse slope to the floor of the Stilling basin. A non-dimensional number using scour parameters llke maximum depth of scour and its location after the end sill, has been used for comparison of the performance of various Stilling basin models. The erodible bed material and the lime for each test fun were kept same during the entire study to facilitate the comparison of the performance.
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Model Studies on Stilling Basins for Pipe Outlets
Irrigation and Drainage Systems, 2001Co-Authors: Arun Goel, D V S VermaAbstract:This paper reports on model studies on energy dissipatorswhich were performed with a view towards developing a shorterand more efficient type of Stilling basin for circular pipeoutlets at low Froude numbers. The Stilling basin models weretested for two pipe outlet diameters. The outlet Froude numberfor testing ranged from 1.70 to 5.50. The studies reported inthis paper expand on the improvement suggested by Goel andVerma (1999). In all, 133 test runs were made on 19 newmodels. Various configurations of Stilling basin models withdifferent sizes, shapes and locations of appurtenances andbasin lengths were tested. The use of a wedge-shaped splitterblock, an impact wall, and the use of wedge-shaped blocks asbaffle blocks resulted in efficient energy dissipation inshorter lengths of Stilling basin. A non-dimensional numbertermed as scour index has been used to compare theperformances of various Stilling basin models. It was foundthat the length of Stilling basin could be reducedconsiderably without affecting the performance by choosing asuitable configuration of the Stilling basin. Of theconfigurations tested, the Stilling basin model M-24 with tworows of wedge-shaped baffle blocks in a basin length of sixtimes the diameter of pipe outlet (6d) performed better incomparison to USBR impact type VI Stilling basin.
