Nonlinear dynamic wave models of gas-liquid flows in technical systems

Author(s):  
R.A. Gasumov ◽  
◽  
V.A. Tolpaev ◽  
K.S. Akhmedov ◽  
A.M. Kravtsov ◽  
...  
2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Weiqin Liu ◽  
Xuemin Song ◽  
Weiguo Wu ◽  
Katsuyuki Suzuki

Extreme waves have caused a lot of ship accidents and casualties. In this paper, a two-dimensional (2D) hydroelastoplasticity method is proposed to study the nonlinear dynamic responses of a container ship in extreme waves. On the one hand, the traditional ultimate strength evaluation is mainly performed using a quasi-static assumption without considering the dynamic wave effect. On the other hand, the dynamic response of a ship induced by a wave is studied based on hydroelasticity theory, which means the ship structural response to large waves is linear. Therefore, a 2D hydroelastoplasticity method that accounts for the coupling between the time-domain wave and ship beam for nonlinear vertical bending moment (VBM) is proposed. In addition, a nonlinear dynamic finite element method (FEM) is also applied for the nonlinear VBM of ship beam. The computational results of the FEM, including the nonlinear VBM and deformational angle, are compared with the results of the 2D hydroelastoplasticity and hydroelasticity. A number of numerical extreme wave models are selected for computations of hydroelasticity-plasticity, hydroelasticity, and FEM. A difference is observed between the nonlinear VBM calculated by FEM and linear VBM calculated by hydroelasticity, and conclusions are drawn.


2014 ◽  
Vol 19 (5) ◽  
pp. 956-965 ◽  
Author(s):  
Cristiana Di Cristo ◽  
Michele Iervolino ◽  
Andrea Vacca
Keyword(s):  

2018 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
John Perdikaris ◽  
Bahram Gharabaghi ◽  
Ramesh Rudra

The accuracy of prediction and ease of use of the three popular flood routing models; simplified dynamic Wave, diffusion wave, and full dynamic wave were evaluated. The models were evaluated along a reach of the Credit River Watershed, in Southern Ontario, Canada. The simplified dynamic wave model showed better accuracy and easier formulation when compared against the diffusion wave and the full dynamic wave models. Indicating that the simplified dynamic wave model can be applied to reaches where the diffusion wave and the full dynamic wave models may not be applicable. The principle novel contributions of the paper are (a) the extension of the flood routing formulations by Keskin and Agiralioglu, (b) the use of a prismatic channel and floodplain with varying top-widths, (c) the validation of the methodology through the application of an event simulation to an actual river reach, and (d) comparison of the modeling results to those obtained using the full dynamic wave model and the diffusion wave models.


2020 ◽  
Vol 43 ◽  
Author(s):  
Valerie F. Reyna ◽  
David A. Broniatowski

Abstract Gilead et al. offer a thoughtful and much-needed treatment of abstraction. However, it fails to build on an extensive literature on abstraction, representational diversity, neurocognition, and psychopathology that provides important constraints and alternative evidence-based conceptions. We draw on conceptions in software engineering, socio-technical systems engineering, and a neurocognitive theory with abstract representations of gist at its core, fuzzy-trace theory.


Author(s):  
E. N. Shiryaeva ◽  
M. A. Polyakov ◽  
D. V. Terent'ev

Complexity of modern metallurgical plants, presence of great number of horizontal and vertical interactions between their various structural subdivisions makes it necessary to apply a systems analysis to elaborate effective measures for stable development of a plant operation. Among such measures, digitalization of a plant is widespread at present. To implement the digitalization it is necessary to have clear vision about links at all the levels of the technological system of a plant. A terminology quoted, accepted in the existing regulatory documents for defining of conceptions, comprising the technological system. It was shown, that the following four hierarchical levels of technological systems are distinguished: technological systems of operations, technological systems of processes, technological systems of production subdivisions and technological systems of plants. A hierarchical scheme of technological systems of hot-rolled sheet production at an integrated steel plant presented. Existing horizontal and vertical links between the basic plant’s shops shown. Peculiarities of flows of material, energy and information at the operation “rolling” of the technological system “hot rolling of a steel sheet” considered. As a technical system of the technological process of the hot rolling, the hot rolling mill was chosen. A structural diagram of the hot rolling mill was elaborated, the mill being consisted of reheating furnaces, roughing and finishing stand groups, with an intermediate roll-table between them, and down-coilers section. Since the rolling stands are the basic structural elements of the hot rolling mill, structural diagrams of a roughing and a finishing stands were elaborated. Results of the systems analysis of the technological and technical systems, hierarchically linked in the process of steel sheet hot rolling, can be applied for perfection of organization structure of the whole plant, as well as for elaboration mathematical models of a system separate elements functioning, which is a necessary condition for a plant digitalization.


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