Experimental research on the maximum backwater height in front of a permeable spur dike in the bend of a spillway chute

2019 ◽  
Vol 19 (6) ◽  
pp. 1841-1850 ◽  
Author(s):  
Jinmeng Yang ◽  
Jing Zhang ◽  
Qinghua Zhang ◽  
Xiaomin Teng ◽  
Wei Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Regression Analysis ◽  
Cross Section ◽  
Experimental Research ◽  
Water Depth ◽  
Momentum Conservation ◽  
Geometric Parameters ◽  
Spur Dike ◽  
The Cross ◽  
Inflow Discharge

Abstract Hydraulic experiments on installing a permeable spur dike at three positions (1/4, 1/2, and 3/4) on the concave bank of the bend of a spillway chute with three angles (45°, 60° and 75°) were carried out for studying the backwater condition in front of the permeable spur dike. Results show that the maximum backwater height occurs at the cross-section where the permeable spur dike meets the concave bank of the bend. A formula for the maximum backwater height was derived by the employment of the principle of momentum conservation, and the formula indicates that the height is influenced by the geometric parameters of the permeable spur dike and the bend, the layout of the spur dike in the bend, and the inflow discharge. Based on experimental data, a regression analysis was implemented on the water depth coefficient in the formula. Furthermore, the maximum backwater height can be obtained through the water depth at the concave bank of the end of bend when the parameters and installing pattern of the permeable spur dike are determined.

Generic Geometric Model for 3D Woven Interlock Composites

2011 ◽  
Vol 399-401 ◽  
pp. 478-485 ◽  
Author(s):  
Ansar Mahmood ◽  
Xin Wei Wang ◽  
Chu Wei Zhou
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Cross Section ◽  
Strong Correlation ◽  
Shape Function ◽  
Geometric Model ◽  
Geometric Parameters ◽  
Internal Geometry ◽  
The Cross

The mechanical properties of 3D woven interlock composites (3DWIC) can be tailored via design of their weave architecture. This paper presents a geometric model called Generic Geometric Model (GG-Model) which delineates the weave architecture of 3DWIC based on its realistic internal geometry i.e. geometry of the cross-section and path of tows. In GG-Model, the cross-section of tows has been described through a novel shape function called “Generic Shape Function (GSF)”. The GG-Model uses manufacturer and weaver specified data to calculate geometric parameters of the 3DWIC and the reinforcing fabric. The GG-Model is then validated by comparing modeled parameters with experimental data. Strong correlation is found between modeled parameters and experimental data.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

scholarly journals Influence of Geometric Parameters on Aerodynamic and Acoustic Performances of Bladeless Fans

2019 ◽  
Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies
Keyword(s):  
Cross Section ◽  
Fluid Dynamic ◽  
Geometric Parameters ◽  
Design Stage ◽  
Air Velocity ◽  
Cross Sectional ◽  
Future Design ◽  
Cross Sectional Profile ◽  
The Cross ◽  
Sectional Profile

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.

The inner shell ionization of atoms by electron impact

1940 ◽  
Vol 36 (1) ◽  
pp. 43-52 ◽  
Author(s):  
E. H. S. Burhop ◽  
H. S. W. Massey
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Cross Section ◽  
Nickel Silver ◽  
Inner Shell Ionization ◽  
Good For ◽  
The Cross ◽  
Shell Ionization ◽  
Good Agreement

Calculations have been made of the cross-section for ionization of the inner shells of atoms by electron impact in the cases of the K-shells of nickel, silver, mercury and of the three L-shells of silver and mercury.The agreement with experiment is reasonably good for the K-shell ionization, but only fair in the case of the rather meagre experimental data available for the L-shell. The values obtained for the relative ionization in the K- and L-shells are in good agreement with those to be expected from experiment.

scholarly journals PROSPECTS OF ANISOGRID LATTICE STRUCTURES USING IN ADAPTERS OF LAUNCH VEHICLE

2019 ◽  
Vol 27 (4) ◽  
pp. 25-34
Author(s):  
Vladislav Arkadiyovych Proroka ◽  
Vladimir Ivanovich Lypovskyi
Keyword(s):  
Numerical Experiment ◽  
Cross Section ◽  
Lattice Structure ◽  
Orthotropic Shell ◽  
Launch Vehicle ◽  
Geometric Parameters ◽  
Carbon Plastic ◽  
Lattice Structures ◽  
Model Calculations ◽  
The Cross

The efficiency of using anisogrid lattice structures in launch vehicle designs, in particular in payload adapters, is investigated. On a specific example of the design of the adapter, which is in operation, it is compared with an anisogrid adapter, which is made of different materials - composite, made by winding, and metal using additive technologies. The performance of the adapter was evaluated by the criterion of minimum mass, subject to the requirements of strength and stability. The initial geometric parameters of the anisogrid lattice structure were determined under the condition that the critical stresses are equal for the symmetric and asymmetric cases of stability loss for the structural orthotropic shell model. Calculations and comparisons were made for composite materials - fiberglass, carbon fiber, organoplastic and boraluminium, as well as metal - AMG6M, BT20. Checking the geometrical parameters calculated on the model of structural orthotropic shell showed that they do not meet the requirements of strength and stability. The choice of geometric parameters of a working adapter design is made by numerical experiment with finite element method. The geometry of the lattice structure of the adapter was parameterized to ensure the variability of two geometric dimensions of the cross section of the longitudinal rib and two geometric dimensions of the cross section of the upper frame. The numerical experiment was performed for the constructions made of carbon plastic and for metals AMG6M, BT20. The results of the calculations showed that the anisogrid lattice structures give a gain on the weight of the adapters, which is up to 50% compared to the designs in operation.

scholarly journals Numerical simulation of the transverse flow over spans of girder bridges

2018 ◽  
Vol 18 (4) ◽  
pp. 362-378
Author(s):  
Yu. A. Gosteev ◽  
A. D. Obukhovskiy ◽  
S. D. Salenko
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Cross Section ◽  
Cross Sections ◽  
Aerodynamic Characteristics ◽  
Transverse Flow ◽  
Single Beam ◽  
Weighted Estimates ◽  
Girder Bridges ◽  
The Cross

Introduction. The technique of numerical modeling of the transverse flow over span structures of bridges on the basis of the two-dimensional URANS (Unsteady Reynolds-averaged Navier-Stokes) approach used in the modern methods and software packages for computational fluid dynamics is verified. The work objective was debugging and experimental substantiation of this technique with the use of the database on the aerodynamic characteristics of the cross-sections of span structures of girder bridges of standard shapes pre-developed by the authors.Materials and Methods. A numerical simulation of the transverse flow of low-turbulent (smooth) and turbulent air flows around the bridge structures in a range of practically interesting attack angles is carried out. SST  k − ω turbulence model was used as the closing one. The technique was preliminarily tested on the check problem for the flow of the rectangular crosssection beams. Calculations were carried out using the licensed ANSYS software.Research Results. The calculated dependences on the attack angle of the aerodynamic coefficients of forces (drag and lift) and the moment of the cross sections of the girder bridges of standard shapes are obtained. These data refer to the span structures at the construction phase (without deck and parapets, without parapets) and operation phase, under the conditions of model smooth and turbulent incoming flow. The latter allows us to outline the boundaries for more weighted estimates of the aerodynamic characteristics of thegirder bridges in a real wind current. The best agreement with the experimental data was obtained from the drag of the cross-section. The magnitude of the lifting force is more sensitive to the presence and extent of the separation regions, so its numerical determination is less accurate. The reproduction of the angle-of-attack effect on the aerodynamic moment of the cross-section is the most challenging for the majority of configurations.Discussion and Conclusions. Comparison of the calculated and experimental data indicates the applicability of the URANS approach to the operational prediction of the aerodynamic characteristics of the single-beam span structures. In the case of multi-beam span structures, where the aerodynamic interference between separate girders plays an important role, the URANS approach must apparently give way to more accurate eddy-resolving methods. The results obtained can be used in the aerodynamic analysis of structures and in practice of the relevant design organizations in the field of transport construction.

scholarly journals Thermochemical properties of liquid alloys along xCu/xSb= 0.2/08 section of the ternary Cu-Sb-Ce system

2017 ◽  
Vol 5 (2) ◽  
pp. 24-29 ◽  
Author(s):  
Natalia Kotova ◽  
Michael Ivanov ◽  
Natalia Usenko
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Cross Section ◽  
Analytical Method ◽  
Composition Dependence ◽  
Liquid Alloys ◽  
Thermochemical Properties ◽  
Enthalpies Of Mixing ◽  
The Cross ◽  
Toop Model

The enthalpies of mixing of liquid alloys of the ternary Cu–Sb–Ce system were studied by high-temperature calorimetry along the cross-section = 0.2/0.8. The composition dependence of these values were modelled using four "geometric" models and also the analytical method of Redlich–Kister–Muggianu. A comparison of the experimental data for the cross section = 0.2/0.8 and simulated values of the enthalpies of mixing showed that the most suitable for describing the properties of liquid alloys of ternary Cu–Sb–Ce system is the Toop model.

scholarly journals Study of the Production Cross-Sections of the Neutron-rich 184Ta and 186Ta

2021 ◽  
Vol 9 (1) ◽  
pp. 25-29
Author(s):  
Susshma Nagarajan ◽  
Deepa Seetharaman ◽  
Gowrishankar Ramadurai
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Cross Section ◽  
Cross Sections ◽  
Good Yield ◽  
Production Cross ◽  
Effective Synthesis ◽  
The Cross

Synthesizing nuclei through reactions that produce a reasonable yield is important for the experimental study of neutron-rich nuclei. In this study, the cross-section values of 184Ta and 186Ta nuclei in various experiments were reviewed and analysed. The experimental data of (n, p), (p, x) and (n, α) reactions were compared to identify the best reaction to produce these nuclei for further study. Our study shows that (n, p) reactions on natural Tungsten targets are the most feasible reactions with a good yield of the neutron-rich Tantalum isotopes. New reactions have been proposed for the effective synthesis of 184Ta and 186Ta using tritium beams on Hafnium targets. The cross-section values of the proposed reactions were calculated by PACE4 software simulations.

scholarly journals THE METHODOLOGY AND SOFTWARE FOR CALCULATING THE ERROR OF CYLINDRICAL SURFACE

2019 ◽  
pp. 151-161
Author(s):  
S. Timofeev ◽  
Maxim Lesunov ◽  
A. Hurtasenko ◽  
I. Maslova
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Geometric Parameters ◽  
Shape Error ◽  
Software Module ◽  
Form Errors ◽  
Correct Assignment ◽  
Special Software ◽  
Shape Errors ◽  
The Cross

Various techniques and devices are used to determine the shape errors of large-sized parts of technological units. This is important for the correct assignment of parameters for further reduction processing by special machines and machine tools. The acquired errors arise for several reasons: 1) large dimensions and weight of rotating parts, 2) the instability of the axis of the rotating part mounted on two support rollers, 3) the available initial and acquired shape error in the cross section of the part. It is important to define the types of form errors of the surfaces, error analysis, prediction and calculation of deviations from roundness in the cross section of the bandage, and the evaluation of cylindricity. Modeling of the process of operation and diagnostics of the unit, development of methods for determining errors, calculation of real values of deviations from the original contour on the basis of reconstruction of the contour of the section becomes important and necessary. These processes are performed using modern CAD systems and software. Obtaining data arrays in the process of measurements and their processing with the help of a special software module that performs an interactive calculation of shape errors with different geometric parameters of the cross-section of the bandage, provides the ability to obtain information about the state of the outer surfaces and parts of the supports on the operating unit. This article presents a method for determining the geometric parameters of the shape in the cross section of the rotation part, algorithms and software for reconstructing the contours of the cross sections of the part and calculating the shape error of the outer cylindrical surfaces

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