Similarity Theory

2008 ◽  
pp. 193-219 ◽  
Keyword(s):  
Similarity Theory

Similarity theory in neutron kinetics and its implications for RFNC—VNIIEF applied research

2011 ◽  
Vol 181 (9) ◽  
pp. 953
Author(s):  
Nikolai B. Babichev ◽  
Pavel S. Bondarev ◽  
Vasilii P. Neznamov
Keyword(s):  
Applied Research ◽  
Similarity Theory ◽  
Neutron Kinetics

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

Structural similitudes of stiffened cylinders

2017 ◽  
Vol 24 (3) ◽  
pp. 527-541 ◽  
Author(s):  
G Petrone ◽  
M Manfredonia ◽  
S De Rosa ◽  
F Franco
Keyword(s):  
Numerical Simulation ◽  
Structural Engineering ◽  
Scaling Laws ◽  
Similarity Theory ◽  
Design Tool ◽  
Engineering Science ◽  
The Finite Element Method ◽  
Engineering Problems ◽  
Incomplete Similarity ◽  
Scaled Models

Similarity theory is a branch of engineering science that deals with establishing conditions of similarity among phenomena and is applied to various fields, such as structural engineering problems, vibration and impact. Tests and numerical simulation of scaled models are still a valuable design tool, whose purpose is to accurately predict the behaviour of large or small prototypes through scaling laws applied to the experimental and numerical results. The aim of this paper is to predict the behaviour of the complete and incomplete similarity of stiffened cylinders by applying distorted scaling laws of the models in similitude. The investigation is performed using models based on the finite element method within commercial software. Two classes of cylinders scaled, with different laws, and, hence, reproducing replicas (exact similitude) and avatars (distorted similitude) are investigated.

Temperature Rise Model of Drum Brake

2013 ◽  
Vol 419 ◽  
pp. 701-705
Author(s):  
Ying Shi Guo ◽  
Chang Wang
Keyword(s):  
Heat Exchange ◽  
Similarity Theory ◽  
Convection Current ◽  
Test Results ◽  
Working Process ◽  
Drum Brake ◽  
Analysis Theory ◽  
Dimension Analysis ◽  
Solution Equation ◽  
Current Heat

In order to analysis the temperature rising rules of vehicle, road conditions and vehicle running state were considered. Process of friction heat generation, radiation heat and convection current exchange during drum brake working process was researched, and temperature rising model of drum brake was established. Under the guidance of similarity theory and dimension analysis theory, convection current heat exchange test of drum brake was carried out, and the solution equation of convection current heat exchange was obtained. Real road test results shows that the temperature rising curves between calculations and test are basically identical and the maximum inaccuracy variables approximately 20%.

The Research on Computation of Researchers Certainty Factor of Bridge's Durability Evaluation Based on the Indeterminate AHP

2014 ◽  
Vol 578-579 ◽  
pp. 1469-1472
Author(s):  
Xiao Zhen Chen ◽  
Xue Jun Zhang
Keyword(s):  
Lower Bound ◽  
Similarity Theory ◽  
Research Result ◽  
Weight Coefficient ◽  
Practical Experience ◽  
Relative Importance ◽  
Certainty Factor ◽  
Average Value ◽  
Judgment Matrix ◽  
Very High

Because of fuzziness, uncertainty of structure and researchers practical experience, it is more practical to express the relative importance of indexes with interval number. Firstly, according to researchers indeterminate judgment matrix, the upper and lower bound matrixes are formed; secondly, the similarity and the differences of the upper and lower bound matrixes of the relative importance matrix from different experts is studied by using the similarity theory of vector; lastly, certainty factor of researchers according to the upper and lower bound matrixes can be calculated, and the average value is regarded as the researchers certainty factor. The certainty factors of researchers upper and lower bound matrixes are consider together, the researchers experience is fully considered and the error from indeterminate judgment matrix to indeterminate judgment matrix is avoided. The result affords basis to calculate the weight coefficient, the research result comparing with the other method showed that the computation accuracy in this paper was very high.

Long-Term Mean Wind Profiles Based on Similarity Theory

2010 ◽  
Vol 136 (3) ◽  
pp. 377-390 ◽  
Author(s):  
Mark Kelly ◽  
Sven-Erik Gryning
Keyword(s):  
Similarity Theory ◽  
Wind Profiles

Experimental Study on Non-Perpendicular Frame Structure of Tall Building

2008 ◽  
Vol 400-402 ◽  
pp. 593-598
Author(s):  
Wei Xing Shi ◽  
Cheng Qing Liu ◽  
Xi Lin Lu ◽  
Song Zhang ◽  
Ying Zhou
Keyword(s):  
Similarity Theory ◽  
Structural Type ◽  
Shaking Table ◽  
Frame Structure ◽  
Scale Model ◽  
Prototype Structure ◽  
Table Model ◽  
Practical Engineering ◽  
Whiplash Effect ◽  
Shaking Table Model Test

A shaking table model test is conducted for Guangzhou West Tower to study its seismic behavior in State Key Laboratory for Disaster Reduction in Civil Engineering at Tongji University. Guangzhou West Tower adopts a new structure system and the significant characteristic of this system is the non-perpendicular frame arranged around the building, acting both as columns and bracings. Based on the similarity theory and member equivalent principle，a 1/80 scale model of this building is made of polymethyl methacrylate(PMMA). The model’s dynamic characteristics, earthquake-resistant behavior, responses of acceleration and deformation under different wave peak values are investigated, then the seismic responses of the prototype structure are deduced and analyzed. The whiplash effect of the prototype structure is studied, and the weak position of the structure is found out. The experiment results demonstrate that it is feasible to apply this structural type to practical engineering. Finally, some suggestions for the engineering design of the prototype structure are put forward.

Comparison of the numerical and self-similar solutions of Sedov’s problem on a point explosion in gas

2020 ◽  
Vol 15 (3-4) ◽  
pp. 212-216
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Korobchinskaya
Keyword(s):  
Gas Dynamics ◽  
Numerical Solutions ◽  
Similarity Theory ◽  
Compressible Medium ◽  
Initial Moment ◽  
Point Explosion ◽  
Perfect Gas ◽  
Gas Dynamics Equations ◽  
Self Similar ◽  
Similar Solutions

Comparative analysis of solutions of Sedov’s problem of a point explosion in gas for the plane case, obtained by the analytical method and using the open software package of computational fluid dynamics OpenFOAM, is carried out. A brief analysis of methods of dimensionality and similarity theory used for the analytical self-similar solution of point explosion problem in a perfect gas (nitrogen) which determined by the density of uncompressed gas, magnitude of released energy, ratio of specific heat capacities and by the index of geometry of the explosion is given. The system of one-dimensional gas dynamics equations for a perfect gas includes the laws of conservation of mass, momentum, and energy is used. It is assumed that at the initial moment of time there is a point explosion with instantaneous release of energy. Analytical self-similar solutions for the Euler and Lagrangian coordinates, mass velocity, pressure, temperature, and density in the case of plane geometry are given. The numerical simulation of considered process in sonicFoam solver of OpenFOAM package built on the PISO algorithm was performed. For numerical modeling the system of differential equations of gas dynamics is used, including the equations of continuity, Navier-Stokes motion for a compressible medium and conservation of internal energy. Initial and boundary conditions were selected in accordance with the obtained analytical solution using the setFieldsDict, blockMeshDict, and uniformFixedValue utilities. The obtained analytical and numerical solutions have a satisfactory agreement.

Model Approach for Displaying Dynamic Filament Displacement during Impregnation of Continuous Fibres Based on the Theory of Similarity – Theory and Modelling

2021 ◽  
Vol 36 (4) ◽  
pp. 423-434
Author(s):  
F. Schulte-Hubbert ◽  
D. Drummer ◽  
L. Hoffmann
Keyword(s):  
Process Parameters ◽  
Similarity Theory ◽  
Dynamic Compaction ◽  
Experimental Investigations ◽  
Process Conditions ◽  
Scaled Model ◽  
Compaction Behavior ◽  
Thermoplastic Matrix ◽  
Analytical Foundation ◽  
Reinforced Thermoplastics

Abstract The underlying process for the production of textile reinforced thermoplastics is the impregnation of dry textile reinforcements with a thermoplastic matrix. The process parameters such as temperature, time and pressure of the impregnation are mainly determined by the permeability of the reinforcement. This results from a complex interaction of hydrodynamic compaction and relaxation behavior caused by textile and process parameters. The foundation for the description and optimization of impregnation progresses is therefore the determination of the pressure-dependent permeability of fibre textiles. Previous experimental investigations have shown that the dynamic compaction behavior during the impregnation of fibre reinforcements with thermoplastics or thermosets can be successfully characterized. However, for most cases, an analytical representation has not been possible due to the complexity of the process. Although it may be possible to reproduce this behavior by numerical calculations, the results need to be confirmed by experiments. This paper lays the analytical foundation for building a scaled model system, based on the theory of similarity, to observe, measure, and evaluate the dynamic compaction behavior of textile reinforcements under controlled process conditions.

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