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.

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 Numerical Simulations of the Flow Field of a Submerged Hydraulic Jump over Triangular Macroroughnesses

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 674
Author(s):  
Amir Ghaderi ◽  
Mehdi Dasineh ◽  
Francesco Aristodemo ◽  
Costanza Aricò
Keyword(s):  
Energy Loss ◽  
Numerical Simulations ◽  
Hydraulic Jump ◽  
Sudden Change ◽  
Air Entrainment ◽  
Streamwise Velocity ◽  
Flow Patterns ◽  
Mean Velocity ◽  
Rough Beds ◽  
Submerged Hydraulic Jump

The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns in the cavity region of a submerged hydraulic jump in the rough beds, especially in the case of triangular macroroughnesses, are not completely understood. The objective of this paper was to numerically investigate via the FLOW-3D model the effects of triangular macroroughnesses on the characteristics of submerged jump, including the longitudinal profile of streamlines, flow patterns in the cavity region, horizontal velocity profiles, streamwise velocity distribution, thickness of the inner layer, bed shear stress coefficient, Turbulent Kinetic Energy (TKE) and energy loss, in different macroroughness arrangements and various inlet Froude numbers (1.7 < Fr1 < 9.3). To verify the accuracy and reliability of the present numerical simulations, literature experimental data were considered.

scholarly journals Explicit prediction of expanding channels hydraulic jump characteristics using gene expression programming approach

2017 ◽  
Vol 49 (3) ◽  
pp. 815-830 ◽  
Author(s):  
Kiyoumars Roushangar ◽  
Roghayeh Ghasempour
Keyword(s):  
Gene Expression ◽  
Hydraulic Jump ◽  
Gene Expression Programming ◽  
Relative Energy ◽  
Expansion Ratio ◽  
Programming Approach ◽  
Jump Length ◽  
Input Parameters ◽  
Sequent Depth ◽  
Better Than

Abstract Hydraulic jump is a useful means of dissipating excess energy of a supercritical flow so that objectionable scour downstream is minimized. The present study applies gene expression programming (GEP) to estimate hydraulic jump characteristics in sudden expanding channels. Three types of expanding channels were considered: channels without appurtenances, with a central sill, and with a negative step. 1,000 experimental data were considered as input data to develop models. The results proved the capability of GEP in predicting hydraulic jump characteristics in expanding channels. It was found that the developed models for channel with a central sill performed better than other channels. In the jump length prediction, the model with input parameters Fr1 and (y2—y1)/y1, and in the sequent depth ratio and relative energy dissipation prediction the model with input parameters Fr1 and y1/B led to more accurate outcomes (Fr1, y1, y2, and B are Froude number, sequent depth of upstream and downstream, and expansion ratio, respectively). Sensitivity analysis showed that Fr1 had the key role in modeling. The GEP models were compared with existing empirical equations and it was found that the GEP models yielded better results. It was also observed that channel and appurtenances geometry affected the modeling.

Hydraulic Jumps in Broken-Back Culverts

2003 ◽  
Vol 1851 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Rollin H. Hotchkiss ◽  
Patrick J. Flanagan ◽  
Kevin Donahoo
Keyword(s):  
Hydraulic Jump ◽  
Design Tool ◽  
Analysis Program ◽  
Experimental Conditions ◽  
Predictive Equations ◽  
Jump Length ◽  
Wide Range ◽  
Downstream Section ◽  
Surface Profiles ◽  
Rating Curves

A broken-back culvert has one or more changes in grade within the prismatic barrel profile. One section of a broken-back culvert is usually steep, with the steep slope contributing to high outlet velocities unless a hydraulic jump forms upstream from the culvert outlet. Predictive equations have been published for a wide range of experimental conditions but still do not describe the hydraulics of a jump as it traverses the steeply sloped section and the most downstream section of a broken-back culvert. A computer program, the Broken-Back Culvert Analysis Program (BCAP), analyzes the hydraulics of circular or box-shaped broken-back culverts and provides a comprehensive design tool for engineers. It predicts whether a hydraulic jump will occur and, if so, where it begins and ends. Analyses are performed for 10 discharges. Outputs include rating curves for headwater and outlet depths and outlet velocity and tabulations of hydraulic parameters for each discharge. The water surface profiles throughout the culvert, except through the hydraulic jump, are computed and are plotted on the screen. Experiments were performed with model culverts to assess the accuracy of the predictive equations in BCAP for headwater depth, the location of a hydraulic jump, and the hydraulic jump length. The predictions for the headwater depth at the culvert inlet matched the experimental observations well, but predictions for hydraulic jump location and length were less satisfactory. BCAP has been used for hundreds of design projects in Nebraska and has been downloaded almost 300 times from at least 22 different states. It is recommended that BCAP be improved as better experimental data become available.

scholarly journals Pulsed Electromagnetic Cross-Well Exploration for Monitoring Permafrost and Examining the Processes of Its Geocryological Changes

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 60
Author(s):  
Viacheslav Glinskikh ◽  
Oleg Nechaev ◽  
Igor Mikhaylov ◽  
Kirill Danilovskiy ◽  
Vladimir Olenchenko
Keyword(s):  
High Performance ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Data Interpretation ◽  
Industrial Facilities ◽  
Wide Range ◽  
Vector Finite Element ◽  
A New Technique ◽  
Pulsed Electromagnetic

This paper is dedicated to the topical problem of examining permafrost’s state and the processes of its geocryological changes by means of geophysical methods. To monitor the cryolithozone, we proposed and scientifically substantiated a new technique of pulsed electromagnetic cross-well sounding. Based on the vector finite-element method, we created a mathematical model of the cross-well sounding process with a pulsed source in a three-dimensional spatially heterogeneous medium. A high-performance parallel computing algorithm was developed and verified. Through realistic geoelectric models of permafrost with a talik under a highway, constructed following the results of electrotomography field data interpretation, we numerically simulated the pulsed sounding on the computing resources of the Siberian Supercomputer Center of SB RAS. The simulation results suggest the proposed system of pulsed electromagnetic cross-well monitoring to be characterized by a high sensitivity to the presence and dimensions of the talik. The devised approach can be oriented to addressing a wide range of issues related to monitoring permafrost rocks under civil and industrial facilities, buildings, and constructions.

Automation and Management of Design Process of the Main Drive for an Innovative Fruits and Vegetables Washer

2021 ◽  
Vol 27 (1) ◽  
pp. 9-17
Author(s):  
V. P. Bui ◽  
◽  
S. S. Gavruishin ◽  
V. B. Phung ◽  
H. M. Dang ◽  
...  
Keyword(s):  
Design Process ◽  
Rational Design ◽  
Fruits And Vegetables ◽  
Rational Solution ◽  
Quality Criteria ◽  
Pareto Optimal ◽  
Optimal Domain ◽  
Wide Range ◽  
A New Technique ◽  
New Generation

A new technique is described, used by the authors to automate the design process of the main drive of a new generation machine intended for industrial washing of fruits and vegetables. To solve the problem of multi-criteria design, the original approach is proposed that uses interconnected mathematical models describing the dynamic behavior, strength reliability and functional characteristics of the machine in a unified information space. The generalized mathematical model includes 12 controlled parameters, 16 functional constraints, and 3 quality criteria. A genetic algorithm was used to find the space of Pareto-optimal solutions. The situational approach was used to select the final rational solution from a set of solutions belonging to the Pareto-optimal domain. The rational design of option the washer found using the proposed approach is compared with the existing ones. The proposed design methodology can be recommended for the design of a wide range of similar mechanical structures.

Closure to “Submerged Hydraulic Jump”

1966 ◽  
Vol 92 (4) ◽  
pp. 154-156
Author(s):  
Nallamuthu Rajaratnam
Keyword(s):  
Hydraulic Jump ◽  
Submerged Hydraulic Jump

Flow and Energy Loss Downstream of Rectangular Sharp-Crested Weirs for Free and Submerged Flows

2021 ◽  
Author(s):  
Mahmud R. Amin ◽  
Nallamuthu Rajaratnam ◽  
David Z. Zhu
Keyword(s):  
Energy Loss ◽  
Flow Regime ◽  
Analytical Study ◽  
Flow Characteristics ◽  
Turbulent Jets ◽  
Flow Regimes ◽  
Impinging Jet ◽  
Relative Energy ◽  
Surface Flow ◽  
Upper Stage

Abstract This work presents an analytical study of the flow and energy loss immediately downstream of rectangular sharp-crested weirs for free and submerged flows, using the theory of plane turbulent jets and the analysis of some relevant studies. The flow regimes downstream of the sharp-crested weir is characterized as the impinging jet and surface flow regimes. Based on the flow characteristics and the downstream tailwater depths, each flow regime is further classified, and the relative energy loss equation is developed. It is found that significant energy loss occurs for the regime of supercritical flow and the upper stage of impinging jet flow. The energy loss for the submerged flow regime is minimal.

Peculiarities of Photorefractive Response in Planar Waveguides Fabricated by Combined Proton and Copper Exchange

1997 ◽  
Vol 06 (03) ◽  
pp. 321-331 ◽  
Author(s):  
Sergey Kostritskii
Keyword(s):  
Experimental Investigation ◽  
Photorefractive Effect ◽  
Planar Waveguides ◽  
Ionic Exchange ◽  
Wide Range ◽  
Infra Red ◽  
Anomalous Character ◽  
A New Technique ◽  
Fabrication Parameters ◽  
Copper Exchange

In this work a photorefractive effect in proton-exchanged planar waveguides on LiNbO 3 crystals is discussed. These waveguides are doped by copper with the aid of a new technique using the low-temperature ionic exchange. The experimental investigation has revealed the anomalous character of the photorefractive response in strongly doped waveguides. Photorefractive measurements are made over a wide range of H +, Cu + and Cu 2+ concentrations, altered by a seriesof oxidation treatments caused by back ionic exchange. Fabrication parameters allowing the realization of high photorefractive sensitivity either in visible or near infra-red ranges are identified.

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