Experimental Study of Sand Sediments Effects on Submerged Hydraulic Jump Properties

2012 ◽  
Vol 212-213 ◽  
pp. 366-371
Author(s):  
Siavash Haghighi ◽  
Mohammad Reza Kavianpour ◽  
Keyvan Nasiri
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Jump ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Sediment Concentration ◽  
Relative Energy ◽  
Sluice Gate ◽  
Jump Length ◽  
Submerged Hydraulic Jump ◽  
Whole Sediments

Abstract. In this study, the effect of sediment concentration on submerged hydraulic jump (SHJ) characteristics such as jump length, submerged depth on the gate and the energy dissipation is investigated. Experiments were carried out in a flume of 46 cm depth, 12 m length. The width of the flume changes from 10 cm (at the entrance) to 60 cm (at the exit). Sediment load and flow concentration have an influence on submerged hydraulic jump characteristics including submerged depth on the gate, jump length and relative energy dissipation. It is shown that at high Froude numbers increasing the suspended sediment concentration to 28.7 gr/l leads to a reduction in the submerged depth on the gate up to 6% and jump length up to 10%. Also, the energy dissipation of the submerged hydraulic jump increases by 4% and turbulence resulting from the jump leads to upright distribution of concentration at the end of the jump. Also in concentrations higher than 30 gr/l, flow is not able to carry the whole sediments and subsequently leads to their deposition in subcritical area and behind the sluice gate.

scholarly journals Predicting submerged hydraulic jump characteristics using machine learning methods

2021 ◽  
Author(s):  
Mohsen Nasrabadi ◽  
Yaser Mehri ◽  
Amin Ghassemi ◽  
Mohammad Hossein Omid
Keyword(s):  
Energy Loss ◽  
Hydraulic Jump ◽  
Relative Energy ◽  
Machine Learning Methods ◽  
Jump Length ◽  
Wide Range ◽  
A New Technique ◽  
Tail Water ◽  
Submerged Hydraulic Jump ◽  
Submergence Depth

Abstract Hydraulic jump typically occurs downstream of hydraulic structures by converting the supercritical to subcritical flow regimes. If the tail-water depth is greater than the secondary depth of the hydraulic jump, the jump will be submerged (SHJ). In these conditions, the momentum equations will not have an analytical solution and a new solution is required. In this study, after dimensional analysis, an experimental study was conducted in a rectangular flume with a length of 9 m, a width of 0.5 m and a depth of 0.45 m in a wide range of Froude numbers (Fr = 3.5 to 11.5) and submergence ratios (Sr = 0.1 to 4). The data were then normalized and divided into two parts of training and testing. A new technique, DGMDH, was used to predict the submerged hydraulic jump characteristics. The results were then compared with the GMDH model. The results showed that DGMDH model estimated the relative submergence depth, jump length, and relative energy loss with accuracy of R2 = 0.9944 and MAPE = 0.038, R2 = 0.9779 and MAPE = 0.0387, and R2 = 0.9932 and MAPE = 0.0192, respectively. While the accuracy of GMDH model for relative submergence depth, jump length, and relative energy loss was respectively R2 = 0.9923 and MAPE = 0.043, R2 = 0.9671 and MAPE = 0.0527, and R2 = 0.9932 and MAPE = 0.0192. Due to superiority of the DGMDH model over the GMDH model, it is recommended to use this model to estimate the submerged hydraulic jump characteristics. Highlight The results showed that DGMDH model have more accurate results than the GMDH model in predicting the relative submergence depth, jump length, and relative energy loss.

scholarly journals Sediment Load and Suspended Sediment Concentration Prediction

2013 ◽  
Vol 1 (No. 1) ◽  
pp. 23-31 ◽  
Author(s):  
Bečvář Martin
Keyword(s):  
Suspended Sediment ◽  
Sediment Yield ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Sediment Concentration ◽  
River Basins ◽  
River Systems ◽  
Sediment Yields ◽  
Suspended Sediment Concentrations ◽  
Annual Sediment

Sediment is a natural component of riverine environments and its presence in river systems is essential. However, in many ways and many places river systems and the landscape have been strongly affected by human activities which have destroyed naturally balanced sediment supply and sediment transport within catchments. As a consequence a number of severe environmental problems and failures have been identified, in particular the link between sediments and chemicals is crucial and has become a subject of major scientific interest. Sediment load and sediment concentration are therefore highly important variables that may play a key role in environment quality assessment and help to evaluate the extent of potential adverse impacts. This paper introduces a methodology to predict sediment loads and suspended sediment concentrations (SSC) in large European river basins. The methodology was developed within an MSc research study that was conducted in order to improve sediment modelling in the GREAT-ER point source pollution river modelling package. Currently GREAT-ER uses suspended sediment concentration of 15 mg/l for all rivers in Europe which is an obvious oversimplification. The basic principle of the methodology to predict sediment concentration is to estimate annual sediment load at the point of interest and the amount of water that transports it. The amount of transported material is then redistributed in that corresponding water volume (using the flow characteristic) which determines sediment concentrations. Across the continent, 44 river basins belonging to major European rivers were investigated. Suspended sediment concentration data were collected from various European basins in order to obtain observed sediment yields. These were then compared against the traditional empiric sediment yield estimators. Three good approaches for sediment yield prediction were introduced based on the comparison. The three approaches were applied to predict annual sediment yields which were consequently translated into suspended sediment concentrations. SSC were predicted at 47 locations widely distributed around Europe. The verification of the methodology was carried out using data from the Czech Republic. Observed SSC were compared against the predicted ones which validated the methodology for SSC prediction.

scholarly journals Decline of Fine Suspended Sediments in the Madeira River Basin (2003–2017)

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 514 ◽  
Author(s):  
Irma Ayes Rivera ◽  
Elisa Armijos Cardenas ◽  
Raúl Espinoza-Villar ◽  
Jhan Espinoza ◽  
Jorge Molina-Carpio ◽  
...  
Keyword(s):  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Water Discharge ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hydropower Potential ◽  
Madeira River ◽  
Fine Suspended Sediment ◽  
Porto Velho ◽  
Madeira River Basin

The Madeira River is the second largest Amazon tributary, contributing up to 50% of the Amazon River’s sediment load. The Madeira has significant hydropower potential, which has started to be used by the Madeira Hydroelectric Complex (MHC), with two large dams along the middle stretch of the river. In this study, fine suspended sediment concentration (FSC) data were assessed downstream of the MHC at the Porto Velho gauging station and at the outlet of each tributary (Beni and Mamoré Rivers, upstream from the MHC), from 2003 to 2017. When comparing the pre-MHC (2003–2008) and post-MHC (2015–2017) periods, a 36% decrease in FSC was observed in the Beni River during the peak months of sediment load (December–March). At Porto Velho, a reduction of 30% was found, which responds to the Upper Madeira Basin and hydroelectric regulation. Concerning water discharge, no significant change occurred, indicating that a lower peak FSC cannot be explained by changes in the peak discharge months. However, lower FSCs are associated with a downward break in the overall time series registered at the outlet of the major sediment supplier—the Beni River—during 2010.

scholarly journals Dynamics of suspended sediment load in the Morava River (Serbia) in the period 1967-2007

2016 ◽  
Vol 18 (1) ◽  
pp. 47-58
Author(s):  
Sanja MANOJLOVIĆ ◽  
Predrag MANOJLOVIĆ ◽  
Mrdjan DJOKIĆ
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Suspended Sediment Load ◽  
Test Results ◽  
Pettitt Test ◽  
Mk Test ◽  
Morava River

The study is concerned with determination of the trend of water discharge, suspended sediment concentration and sediment load in the most downstream profile of the Velika Morava River in the period 1967-2007. The gradual trend test (Mann–Kendall test – MK test) and abrupt change test (Pettitt test) have been employed on annual, seasonal and monthly water discharge, suspended sediment concentration and suspended sediment load for the given time series. Both the Mann–Kendall and Pettitt tests indicate that water discharge showed no significant annual trend or abrupt shift. However, annual suspended sediment concentration and sediment load showed significant decreasing trends (α=0.001). The average decrease of suspended sediment load transport amounted to 3.15 t/km2/yr. The Pettitt test results showed that the change-point year was detected in 1982. The average specific sediment load amounted to 134.6 t/km2/yr before the transition year, and 36.5 t/km2/yr after the transition year, i.e., it was reduced by 73 %. In the intra-annual distribution, the MK test results indicate that the most pronounced decreasing trend (α=0.001) of the sediment load is during summer and winter. Strong seasonal and monthly variability in sediment load was found. Sediment was strongly transported during spring months, in the period of frequent flood events. Almost 50% of the annual sediment is transported during March, April and May. Analysis of the discharge and suspended sediment concentration relationship revealed the existence of hysteresis loop in the shape of figure eight. The results of this study confirm the complex and heterogeneous nature of sediment response in the Velika Morava River.

scholarly journals Sediment Dynamics in a Small, 2Nd Order Urban River Awba Catchment, Ibadan, Nigeria

2014 ◽  
Vol 7 (1-2) ◽  
pp. 23-28 ◽  
Author(s):  
Aderemi Adediji ◽  
Olutoyin A. Fashae
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Sediment Concentration ◽  
Sediment Dynamics ◽  
Storm Flow ◽  
Weekly Sample ◽  
The University ◽  
Ibadan Nigeria

Abstract The sediment dynamics in a small 2nd order catchment of River Awba in the territory of the University of Ibadan, Nigeria was investigated between January and December 2012. The river was gauged by daily measurements of water level as well as sampling of water for determination of suspended sediment load. In this regard, apart from weekly sample, twelve (12) storm flow events which occurred during the day were sampled for determination of suspended sediment concentration. The results showed that during the storms the suspended sediment concentration varied between 636 mg/l in May and 3641.5 mg/l in September, with a mean of 2136.8 mg/l. Also, the value of monthly suspended sediment yield ranged from 10.85 kg in January to 288.4 kg in October with a mean of 89.5 kg. The variability in monthly sediment load closely followed the trend of monthly rainfall in the study area. However, in order to minimize the storm runoff and sediment load generated from the rainstorms events, the paved surfaces within the study catchment should be grassed with the planting of some few tree species. This could further reduce the rate of floods occurrence.

scholarly journals Predicting the relative energy dissipation of hydraulic jump in rough and smooth bed compound channels using SVM

2018 ◽  
Vol 19 (4) ◽  
pp. 1110-1119
Author(s):  
Seyed Mahdi Saghebian
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Jump ◽  
Dominant Role ◽  
Rectangular Channel ◽  
Relative Energy ◽  
Support Vector ◽  
Channel Models ◽  
Rough Bed ◽  
Different Shapes ◽  
Rough Beds

Abstract Channels with different shapes and bed conditions are used as useful appurtenances to dissipate the extra energy of a hydraulic jump. Accurate prediction of hydraulic jump energy dissipation is important in design of hydraulic structures. In the current study, hydraulic jump energy dissipation was assessed in channels with different shapes and bed conditions (i.e. smooth and rough beds) using the support vector machine (SVM) as an intelligence approach. Five series of experimental datasets were applied to develop the models. The results showed that the SVM model is successful in estimating the relative energy dissipation. For the smooth bed, it was observed that the sloping channel models with steps performed more successfully than rectangular and trapezoidal channels and the step height is an effective variable in the estimation process. For the rough bed, the trapezoidal channel models were more accurate than the rectangular channel. It was found that rough element geometry is effective in estimation of the energy dissipation. The result showed that the models of rough channels led to better predictions. The sensitivity analysis results revealed that Froude number had the more dominant role in the modeling. Comparison among SVM and two other intelligence approaches showed that SVM is more successful in the prediction process.

scholarly journals Recent changes in climate, hydrology and sediment load in the Wadi Abd, Algeria (1970–2010)

2016 ◽  
Vol 20 (4) ◽  
pp. 1355-1372 ◽  
Author(s):  
Mohammed Achite ◽  
Sylvain Ouillon
Keyword(s):  
Sediment Yield ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Sediment Concentration ◽  
Sediment Flux ◽  
Rating Curve ◽  
Cascading Effects ◽  
Suspended Particulate ◽  
Hysteresis Phenomena ◽  
Hydrological Regimes

Abstract. Here we investigate the changes of temperature, precipitation, river runoff and sediment transport in the Wadi Abd in northwest Algeria over a time series of 40 hydrological years (1970–2010). Temperature increased and precipitation decreased with the reduction in rainfall being relatively higher during the rainy season. A shift towards an earlier onset of first rains during summer was also found with cascading effects on hydrology (hydrological regimes, vegetation, etc.) and thus on erosion and sediment yield. During the 1980s, the flow regime shifted from perennial to intermittent with an amplification of the variations of discharge and a modification of the sediment regime with higher and more irregular suspended particulate flux. Sediment flux was shown to almost double every decade from the 1970s to the 2000s. The sediment regime shifted from two equivalent seasons of sediment yield (spring and fall) to a single major season regime. In the 2000s, autumn produced over 4 times more sediment than spring. The enhanced scatter of the C–Q pairs denotes an increase of hysteresis phenomena in the Wadi Abd that is probably related to the change in the hydrologic regime. At the end of the period, due to irregularity of the discharge, the ability of a rating curve to derive suspended sediment concentration from river discharge was poor.

scholarly journals Suspended Sediment Transport from the Dokriani Glacier in the Garhwal Himalayas

2003 ◽  
Vol 34 (3) ◽  
pp. 221-244 ◽  
Author(s):  
Pratap Singh ◽  
K. S. Ramasatri ◽  
Naresh Kumar ◽  
N. K. Bhatnagar
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Drainage Basin ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Hydro Power ◽  
Garhwal Himalayas ◽  
Suspended Sediment Concentrations ◽  
June July

Estimation of sediment load from glacierized basins is very important for planning, designing, installation and operation of hydro-power projects, including management of reservoirs. In the present study, an assessment of suspended sediment concentration, load, yield and erosion rate has been undertaken for the Dokriani Glacier drainage basin located in the Garhwal Himalayas. About 60% of the total drainage area of this basin is glacierized. Data were collected for four ablation seasons (1995-1998). The mean daily suspended sediment concentrations for June, July, August and September were 452, 933, 965 and 275 mg 1-1, respectively, indicating highest suspended sediment concentration in August, followed by July. Similar trends were also found for the sediment load and about 88% of the total suspended sediment load of the melt period was transported during the months of July and August. Sediment yield for the study basin was computed to be about 2,800 t km-2 yr-1, which is comparable with glacierized basins (10-30% glacierized) in the Pamir region. For the entire ablation period, the erosion from the Dokriani Glacier basin is estimated to be about 1.0 mm. There was a poor relationship between suspended sediment concentration and discharge. The average percentages of clay, silt and sand were found to be 1.4, 67.3 and 31.3%, respectively, which suggest maximum content of silt followed by sand. There was limited variation in the content of clay, silt and sand in the suspended sediment during the ablation period.

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