scholarly journals Hydraulic parameters in the area of the main dam intake structure of the river

2021 ◽  
Vol 264 ◽  
pp. 03002
Author(s):  
Dilshod Bazarov ◽  
Sukhrob Umarov ◽  
Rustam Oymatov ◽  
Farokhiddin Uljaev ◽  
Khumoyun Rayimov ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Cross Section ◽  
Functional Dependence ◽  
Hydraulic Parameters ◽  
Flow Depth ◽  
Main Structure ◽  
Depth Dependence ◽  
Study Results ◽  
Functional Graph ◽  
Intake Structure

The article presents the study results of changes in flow hydraulic parameters and morphometric elements of the river in the area of the main dam intake structure. A model for studying the direction of flow and other parameters of the flow in the area of the main structure for obtaining water from the Amudarya without a dam has been developed. A functional graph of the depth dependence of the expenditure on the study object was obtained. Graphs of the functional dependence of the diurnal cross-section of the riverbed on the flow depth and the variation of the flow velocity depending on the flow depth were constructed. The direction and distribution of the flow in the area of the main dam intake structure were studied.

Investigation of the influence of the flow structure on the accuracy of flow measurement before a hydrometric structure in an open channel

2020 ◽  
pp. 41-44
Author(s):  
Anatoly Kusher
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Water Flow ◽  
Flow Measurement ◽  
Water Discharge ◽  
Critical Depth ◽  
Flow Measurements ◽  
Study Results ◽  
Flow Velocity Profile ◽  
Upstream Flow

The reliability of water flow measurement in irrigational canals depends on the measurement method and design features of the flow-measuring structure and the upstream flow velocity profile. The flow velocity profile is a function of the channel geometry and wall roughness. The article presents the study results of the influence of the upstream flow velocity profile on the discharge measurement accuracy. For this, the physical and numerical modeling of two structures was carried out: a critical depth flume and a hydrometric overfall in a rectangular channel. According to the data of numerical simulation of the critical depth flume with a uniform and parabolic (1/7) velocity profile in the upstream channel, the values of water discharge differ very little from the experimental values in the laboratory model with a similar geometry (δ < 2 %). In contrast to the critical depth flume, a change in the velocity profile only due to an increase in the height of the bottom roughness by 3 mm causes a decrease of the overfall discharge coefficient by 4…5 %. According to the results of the numerical and physical modeling, it was found that an increase of backwater by hydrometric structure reduces the influence of the upstream flow velocity profile and increases the reliability of water flow measurements.

scholarly journals The possibilities of using group regression in the analysis of the diameter structure development in selection forests of Tara

2002 ◽  
pp. 79-89 ◽  
Author(s):  
Slobodanka Mitrovic ◽  
Stanisa Bankovic
Keyword(s):  
Mathematical Model ◽  
Future Development ◽  
Functional Dependence ◽  
Primary Objective ◽  
Structure Development ◽  
Study Results ◽  
The Future ◽  
Diameter Structure ◽  
Group Regression ◽  
Diameter Classes

Based on the presented study results, it can be concluded that the distribution of tree numbers per diameter degrees (diameter structure) in the four measurements of the compartments 51 and 75, did not change. It was also concluded that one functional dependence could be applied for both compartments N=e5,9?e?0,39*d The result of the above is that also in the following measurements, the diameter structure will remain unchanged, in cases of the same or similar selection cuttings both by the scope and by the distribution of felled trees per diameter classes The primary objective of this type of study is to predict, based on a mathematical model of diameter structure development, effect of the scope of selection cuttings and the number of recruitments on the diameter structure, and the simulation of growth, the distribution of trees per diameter classes in the following measurement or measurements, i.e. to foresee the future development of selection stands.

scholarly journals PENGARUH VEGETASI TERHADAP TAHANAN ALIRAN PADA SALURAN IRIGASI

2019 ◽  
Vol 2 (2) ◽  
pp. 107-113
Author(s):  
I.E. Sulastri Sihotang ◽  
Eldina Fatimah ◽  
Masimin Masimin
Keyword(s):  
Flow Velocity ◽  
Field Observation ◽  
Flow Resistance ◽  
Grid Method ◽  
Flow Depth ◽  
Secondary Channel ◽  
Irrigation Channel ◽  
Velocity Flow

Irrigation channel in D.I. Timbang Deli, Deli Serdang district Sumut province has a total area of 520 Ha and a 5000 meter long secondary channel. Irrigation channel in D.I. Timbang Deli overgrown vegetation at the base and wall of the channel so it is expected to affect roughness. The objective of the study was the flow resistance with the variation of vegetation volume to the variation of the discharge. The method used in this study is field observation by measuring flow velocity, flow depth and vegetation volume (VT) on trapezoidal tract width of 3.75 m and height of 0.90 m along 154 m. Measurements were performed on 3 points of upstream, middle and downstream channels and 5 transverse dots X1 through X5 4 times with D1 debit variation of 1.32 m³/s and D2 of 0.98 m³/s. The dominant vegetation channels are rigid. Measurement velocity using current meter while for vegetation volume (VT) using grid method. The results showed that vegetation volume VT0 (0,00 m³/0,00%), VT1 (52,417 m³/21,14%), VT2 (70,7921 m³/24,51%) and VT3 (83,053 m³/30,42%). It is seen that the increase in vegetation volume can affect the flow resistance. The result of measurement increased the resistance of flow to VT0 0,052, VT1 equal to 0,062 with percentage 16,13%, VT2 equal to 0,108 with percentage 51,85% and VT3 equal to 0,122 with percentage 57,37% atD1. Meanwhile, at D2 there is an increase of flow resistance to VT0 by 0,044, VT1 is 0,052 with percentage 15,38%, VT2 equal to 0,058 with percentage 24,14% and VT3 equal to 0,070 with percentage 37,14%. This shows that the flow resistance VT0 is smaller than the flow resistance VT1, VT2 and VT3. From the above results are expected to conduct O P channels by surrounding communities and related government.

A measurement of the cross-section for detachment of electrons from H – by electron impact

1967 ◽  
Vol 299 (1459) ◽  
pp. 525-537 ◽  
Keyword(s):  
Cross Section ◽  
Born Approximation ◽  
Theoretical Calculations ◽  
Functional Dependence ◽  
Incident Electron ◽  
Incident Electron Energy ◽  
Measured Cross Section ◽  
Neutral Particles ◽  
Beam Method ◽  
The Cross

A crossed beam method has been used to measure the cross-section for the production of neutral particles in single collisions of electrons with H - ions at incident electron energies from 9 to 500 eV. The measured cross-section reaches a maximum of 50 Å 2 at an energy of 14 eV, and may be represented by the function Q = (1-1.6/( E log 10 E ) ½ )950/ E log 10 E /0·92, where the cross-section Q is in units of Å 2 and the incident electron energy E in units of electronvolts. The magnitude and functional dependence of the cross-section agree well with theoretical calculations based on the Bethe-Born approximation at energies above 20 eV.

Parametric Study of Beam to Column Extended Endplate Connection in Fire

2012 ◽  
Vol 594-597 ◽  
pp. 779-784
Author(s):  
Meng Wang
Keyword(s):  
Cross Section ◽  
Failure Modes ◽  
Numerical Study ◽  
Numerical Models ◽  
Great Influence ◽  
Load Ratio ◽  
Simulation Methodology ◽  
Study Results ◽  
Endplate Connection ◽  
In Fire

In this paper, numerical study results using ABAQUS are presents to demonstrate the failure modes and the behaviour of endplate connection with different parameters at elevated temperature. Numerical models and simulation methodology are first validated by the comparison to experimental data. Then the behaviour of beam and the failure modes endplate connection with different parameters- including beam span, beam load ratio, column cross section, endplate type- are studied. It can be concluded that all these parameters has a effects on the behaviour of the connection, while some parameters has a great influence on the survivability of the joint.

The nature of saltation and of ‘bed-load’ transport in water

1973 ◽  
Vol 332 (1591) ◽  
pp. 473-504 ◽  
Keyword(s):  
Flow Velocity ◽  
Bed Load ◽  
Flow Depth ◽  
Mean Flow ◽  
Stream Power ◽  
Fluid Turbulence ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Mean ◽  
Mean Flow Velocity

Owing to observational difficulties the distinction between a ‘suspended’ load of solids transported by a stream and a ‘ bed-load ’ has long remained undefined. Recently, however, certain critical experiments have thrown much light on the nature of bed-load transport. In particular, it has been shown that bed-load transport, by saltation, occurs in the absence of fluid turbulence and must therefore be due to a separate dynamic process from that of transport in suspension by the internal eddy motion of a turbulent fluid. It has been further shown that the forward motion of saltating solids is opposed by a frictional force of the same order as the immersed weight of the solids, the friction coefficient approximating to that given by the angle of slip. The maintenance of steady motion therefore requires a predictable rate of energy dissipation by the transporting fluid. The fluid thrust necessary to maintain the motion is shown to be exerted by virtue of a mean slip velocity which is predictable in the same way as, and approxim ates to, the terminal fall velocity of the solid. The mean thrust, and therefore the transport rate of saltating solids, are therefore predictable in terms of the fluid velocity close to the bed, at a distance from it, within the saltation zone, of a ‘centre of fluid thrust’ analogous to the ‘centre of pressure’. This velocity, which is not directly measurable in water streams, can be got from a knowledge of stream depth and mean flow velocity. Thus a basic energy equation is obtained relating the rate of transporting work done to available fluid transporting power. This is shown to be applicable to the transport both of wind-blown sand, and of water-driven solids of all sizes and larger than that of medium sand. Though the mean flow velocity is itself unpredictable, the total stream power, which is the product of this quantity times the bed shear stress, is readily measurable. But since the mean flow velocity is an increasing function of flow depth, the transport of solids expressed in terms of total stream power must decrease with increasing flow depth/grain size ratio. This considerable variation with flow depth has not been previously recognised. It explains the gross inconsistencies found in the existing experimental data. The theoretical variation is shown to approximate very closely to that found in recent critical experiments in which transport rates were measured at different constant flow depths. The theory, which is largely confirmed by these and other earlier experiments, indicates that suspension by fluid turbulence of mineral solids larger than those of medium sands does not become appreciable until the bed shear stress is increased to a value exceeding 12 times its threshold value for the bed material considered. This range of unsuspended transport decreases rapidly, however, as the grain size is reduced till, at a certain critical size, suspension should occur at the threshold of bed movement.

scholarly journals Effects of Using Channelling Devices to Increase Efficiency of Hydrokinetic Devices

2015 ◽  
Vol 52 (2) ◽  
pp. 3-12
Author(s):  
A. Kalnacs ◽  
J. Kalnacs ◽  
A. Mutule ◽  
V. Entins
Keyword(s):  
Flow Control ◽  
Flow Velocity ◽  
Cross Section ◽  
Power Output ◽  
High Importance ◽  
Different Types ◽  
The Cross ◽  
Increase Efficiency ◽  
Flow Velocities

Abstract In the rivers of Latvia and of many other countries the flow velocity in the places that are most suitable for installation of hydrokinetic devices is 0.4 to 0.9 m/s. In a stream or a river the hydrokinetic devices can reach full efficiency starting from about twice higher flow velocities. It is advisable to at least double this velocity thus increasing the efficiency and power output of the hydrokinetic devices installed in such places. Since Latvia has abundance of slow rivers and almost none are fast, research in this field is of high importance. Diversified technical methods are known that allow increasing substantially the efficiency of hydrokinetic devices. These methods include the use of diffusers, concentrators, different types of other channelling devices and means of flow control. Desirable effects are achieved through changing the cross-section and/or direction of a flow, its pressure, minimizing the turbulence, etc. This work substantiates the use of such devices for increasing the efficiency of hydrokinetic devices. A method is proposed for evaluation of the effects on power output gained owing to the use of channelling devices. Results show that the efficiency of hydrokinetic devices can be increased by at least 110%.

Member distortional buckling behaviour of hybrid double-I-box beams

2018 ◽  
Vol 45 (8) ◽  
pp. 605-622 ◽  
Author(s):  
M.S. Deepak ◽  
V.M. Shanthi
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Parametric Study ◽  
Flexural Rigidity ◽  
Numerical Study ◽  
Plate Thickness ◽  
Distortional Buckling ◽  
Study Results ◽  
Box Beams ◽  
The Moment

This paper compiles the experimental and finite-element parametric study on member distortional buckling behaviour of new built-up metal hybrid double-I-box beams (HDIBBs). The cross-section of this built-up beam is unique and looks similar to the shape of a double-I-box fabricated using four channel sections. The flange plates were provided with an intermediate stiffener. In these built-up beams there is more material in the flange portions far away from the horizontal centroidal axis of their cross-section. Hence, there is an increase in the flexural rigidity that enhances the moment capacity of the beam, under major axis bending. The geometry consists of torsionally rigid closed-box web portion that provides high resistance to minor axis lateral-buckling. The varying parameters considered were the ratio of yield stresses of the flange to the web steel plates, the ratio of breadth to the depth of the section, and the flange plate thickness. In the experimental programme, all the HDIBB members failed due to kinds of distortional buckling which was identified by web buckling and flange twist along edges. The results revealed that when flange plate slenderness increases there is a drop in the moment resistance capacity of the beams. The numerical study was performed using ABAQUS software. In comparison, there was good agreement between experimental and numerical results. The validated finite element models were further extended to perform parametric studies on ideal HDIBB models. Both the experimental and parametric study results were compared with the predicted strengths using effective width method equations specified in the Euro code standards EN 3-1-3. It was found that the current Euro code design rules slightly over-estimate the distortional buckling resistance capacity of closed form built-up cold-formed steel members. A new design equation was formulated and recommended for estimating the reduction in distortional buckling moment resistance capacity for HDIBBs.

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