scholarly journals A Multiphysics Analysis of Coupled Electromagnetic-Thermal Phenomena in Cable Lines

2021 ◽  
Author(s):  
Artur Cywiński ◽  
Krzysztof Chwastek
Keyword(s):  
Numerical Modeling ◽  
Heat Exchange ◽  
Numerical Models ◽  
Power Engineering ◽  
Commercial Software ◽  
Free Air ◽  
Cable Systems ◽  
Cable Lines ◽  
Thermal Phenomena ◽  
Air Modeling

The paper is focused on numerical modeling of multi-strand cable lines placed in free air. Modeling is carried out within the framework of the so-called multi-physics approach using commercial software. The paper describes in detail the steps undertaken to develop realistic, reliable numerical models of power engineering cables, taking into account their geometries and heat exchange conditions. The results might be of interest to the designers of multi-strand cable systems.

scholarly journals A Multiphysics Analysis of Coupled Electromagnetic-Thermal Phenomena in Cable Lines

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2008
Author(s):  
Artur Cywiński ◽  
Krzysztof Chwastek
Keyword(s):  
Numerical Modeling ◽  
Heat Exchange ◽  
Numerical Models ◽  
Power Engineering ◽  
Commercial Software ◽  
Free Air ◽  
Cable Systems ◽  
Cable Lines ◽  
Thermal Phenomena ◽  
Air Modeling

The paper is focused on numerical modeling of multi-strand cable lines placed in free air. Modeling is carried out within the framework of the so-called multi-physics approach using commercial software. The paper describes in detail the steps undertaken to develop realistic, reliable numerical models of power engineering cables, taking into account their geometries and heat exchange conditions. The results might be of interest to the designers of multi-strand cable systems.

scholarly journals Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 458
Author(s):  
Drew C. Baird ◽  
Benjamin Abban ◽  
S. Michael Scurlock ◽  
Steven B. Abt ◽  
Christopher I. Thornton
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Numerical Models ◽  
Hydraulic Performance ◽  
Physical Models ◽  
Protection Measures ◽  
Design Engineers ◽  
Model Study ◽  
Study Results ◽  
Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

scholarly journals Numerical modeling of the hydraulic impact of riparian vegetation

2018 ◽  
Vol 44 ◽  
pp. 00194
Author(s):  
Krzysztof Wolski ◽  
Tomasz Tymiński ◽  
Grzegorz Chrobak
Keyword(s):  
Numerical Modeling ◽  
Riparian Vegetation ◽  
Water Surface ◽  
Numerical Models ◽  
Three Dimensional ◽  
Careful Examination ◽  
Impact Structure ◽  
Hydraulic Impact ◽  
Vegetation Zones ◽  
Maximal Shear Stress

This paper presents results of numerical modelling of riverbed segment with riparian vegetation performed with use of CCHE2 software. Vegetation zones are places where dynamic of water flow increases. Therefore, there is a need of careful examination of hydraulic impact structure of such zones. Accurate research is necessary and should be performed with use of physical or numerical models, two or three dimensional. Paper presents distribution of velocity and area of water surface for two variants of vegetation deposition acquired in CCHE2D software and modelled for riverbed with distinctive riparian vegetation. Results point to significant (30–40%) increase of maximal velocities in riverbed with riparian vegetation, while directly near the vegetation there were zones with very low velocities. Local damming occurs before vegetal zone. Maximal shear stress in zones with increased velocity is significantly augmented compared to conditions with no vegetation, which can cause more intensive erosion in those zones

scholarly journals Numerical Modeling of a Punch Penetration Test Using the Discrete Element Method

2020 ◽  
Vol 28 (2) ◽  
pp. 1-7
Author(s):  
Rouhollah Basirat ◽  
Jafar Khademi Hamidi
Keyword(s):  
Numerical Modeling ◽  
Discrete Element Method ◽  
Numerical Models ◽  
Confining Pressure ◽  
Discrete Element ◽  
Numerical Results ◽  
Strength Parameter ◽  
Penetration Test ◽  
Strength Parameters ◽  
Element Method

AbstractUnderstanding the brittleness of rock has a crucial importance in rock engineering applications such as the mechanical excavation of rock. In this study, numerical modeling of a punch penetration test is performed using the Discrete Element Method (DEM). The Peak Strength Index (PSI) as a function of the brittleness index was calculated using the axial load and a penetration graph obtained from numerical models. In the first step, the numerical model was verified by experimental results. The results obtained from the numerical modeling showed a good agreement with those obtained from the experimental tests. The propagation path was also simulated using Voronoi meshing. The fracture was created under the indenter in the first step, and then radial fractures were propagated. The effects of confining pressure and strength parameters on the PSI were subsequently investigated. The numerical results showed that the PSI increases with enhancing the confining pressure and the strength parameter of the rock, including cohesion and the friction angle. A new relationship between the strength parameters and PSI was also introduced based on two variable regressions of the numerical results.

scholarly journals Numerical modeling of hiding properties of underwater acoUStic communication signals with linear sweep of the carrier

2020 ◽  
Author(s):  
К.Г. Кебкал
Keyword(s):  
Numerical Modeling ◽  
Continuous Spectrum ◽  
Gaussian Noise ◽  
Data Exchange ◽  
Numerical Models ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Communication Signals ◽  
Communication Signal ◽  
Spectrum Spread

На результатах численного моделирования продемонстрировано, что распределения вероятностей огибающей и фазы смеси гауссова шума и (слабого) гидроакустического сигнала связи, характеризуемого линейной разверткой несущей, могут иметь исчезающе малые отличия от аналогичных распределений, характерных для просто гауссова шума. Использование непрерывного расширения спектра сигнала связи может представлять интерес для задач скрытого обмена данными, в которых обнаружение сеанса связи устройствами перехвата должно быть затруднительным или невозможным. С применением численных моделей проанализированы возможности использования сигналов с непрерывным расширением спектра для скрытой цифровой гидроакустической связи посредством штатных приемоизлучающих гидроакустических систем, находящихся на вооружении действующих кораблей. Based on the results of the numerical modeling, the vanishingly small differences between the probability distributions of the envelope and phase of the sum of Gaussian noise and (weak) underwater acoustic signal with linear carrier sweep, and the same distributions for the Gaussian noise all alone are demonstrated. Utilization of the continuous spectrum spread of the communication signal may be applied to the task of covert data exchange, where detection of the communication session by the intercepting equipment must be complicated or impossible. Using numerical models, we analyzed the capabilities of implementation of the signals with continuous spectrum spread for covert digital underwater acoustic communications through the standard underwater acoustic transducers, which are in service on the operational ready vessels.

Experimental Validation of Computer Models for Food and Polymer Extrusion

2003 ◽  
Author(s):  
Yogesh Jaluria
Keyword(s):  
Numerical Modeling ◽  
Numerical Models ◽  
Strong Support ◽  
Chemical Conversion ◽  
Operating Conditions ◽  
Experimental Results ◽  
Twin Screw Extruders ◽  
Twin Screw ◽  
Temperature Dependent Properties ◽  
Good Agreement

The accuracy and validity of the mathematical and numerical modeling of extruders for polymers and for food are considered in terms of experimental results obtained on typical full-size single and twin-screw extruders. The fluid is treated as non-Newtonian and with strong temperature-dependent properties. The chemical conversion of food during extrusion is also considered. The numerical modeling is employed for steady-state transport, for a range of operating conditions. Following grid-independence studies, the results obtained are first considered in terms of the expected physical behavior of the process, yielding good agreement with observations presented in the literature. The results are then compared with detailed and qualitative experimental results available from previous investigations to evaluate their accuracy. Good agreement with experimental data is obtained, lending strong support to the mathematical and numerical models.

2-D AUTOMATIC COMPOSITION OF NODAL VALUES FROM NUMERICAL MODEL USING SCRIPT PROGRAMMING

2013 ◽  
Vol 62 (1) ◽  
Author(s):  
Rudi Heriansyah
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Finite Difference ◽  
Two Dimensional ◽  
Commercial Software ◽  
One Dimensional ◽  
Automatic Composition ◽  
The Individual ◽  
Individual Nodes

There are many commercial software to perform numerical modeling based on finite element (FEM) and finite difference (FDM) methods. It is often a requirement to the designer, that the values of the individual nodes in the numerical model are known. Usually, these softwares provide two methods to achieve this; firstly, by clicking directly onto the nodes of interest and secondly, by saving or exporting the whole nodal values to an external file. The former way is appropriate for models with small number of nodes, but as the number of nodes increases, it is no longer an efficient or effective way. Through the latter method, all nodal values are obtained, however the values are one-dimensional, and in some cases, only certain nodal values are required for presentation. In this paper, an algorithm for automatic composition of nodal values obtained from the second method mentioned above. The composed nodal values will be in two-dimensional form as this is the format used for uniform shaped model (square or rectangular). Since numerical softwares usually have facilities to save the data in a spreadsheet format, the proposed algorithm is implemented in this environment by using spreadsheet script programming.

THE MODELING OF THE TEMPERATURE CHANGES AND DISTRIBUTION IN THE MYOCARDIUM

2020 ◽  
Vol 20 (04) ◽  
pp. 1950061
Author(s):  
VLADYSLAV SHLYKOV ◽  
VITALII KOTOVSKYI ◽  
NIKOLAJ VIŠNIAKOV ◽  
ANDŽELA ŠEŠOK
Keyword(s):  
Numerical Modeling ◽  
Cardiopulmonary Bypass ◽  
Heat Exchange ◽  
Temperature Gradient ◽  
3D Model ◽  
Noninvasive Monitoring ◽  
Temperature Changes ◽  
Thermographic Camera ◽  
Diagnostic Criterion

This paper investigates the opportunities of applying the methods of noninvasive contactless diagnostics and numerical modeling for assessing the temperature gradient on the surface of the myocardium. These changes are observed on the surface of myocardium during hypo and hyperthermal processes, precisely during cardiopulmonary bypass (CPB). The 3D model of heat exchange in the myocardium is developed in the system MSC Sinda. Results of the performed measurements in the heart show that a noninvasive monitoring of the heart temperature using a thermographic camera in (CPB) conditions enables reliable measuring of the temperature of the myocardium during hypo and hyperthermal processes. The gradient of temperature on the surface of the heart may be usable as a diagnostic criterion for establishing ischemic zones on the surface of the myocardium.

scholarly journals Study of Current- and Wave-Induced Sediment Transport in the Nowshahr Port Entrance Channel by Using Numerical Modeling and Field Measurements

2020 ◽  
Vol 8 (4) ◽  
pp. 284 ◽  
Author(s):  
Ayyuob Mahmoodi ◽  
Mir Ahmad Lashteh Neshaei ◽  
Abbas Mansouri ◽  
Mahmood Shafai Bejestan
Keyword(s):  
Numerical Modeling ◽  
Caspian Sea ◽  
Recirculation Zone ◽  
Numerical Models ◽  
Field Measurements ◽  
Sediment Sources ◽  
The Caspian Sea ◽  
Access Channel ◽  
Negative Impacts ◽  
Wave Induced

The Nowshahr port in the southern coastlines of the Caspian Sea is among the oldest northern ports of Iran, first commissioned in the year 1939. In recent years, this port has been faced with severe sedimentation issues in and around its entrance that has had negative impacts on the operability of the port. The present study aims at identifying major reasons for severe sedimentation in the port entrance. First, field measurements were evaluated to gain an in-depth view of the hydrodynamics of the study area. Numerical models then were calibrated and validated against existing field measurements. Results of numerical modeling indicated that wind-induced current is dominant in the Caspian Sea. The numerical results also indicated that in the case of an eastward current direction, the interaction between current and the western breakwater arm would lead to the formation of a separation zone and a recirculation zone to the east of the port entrance region. This eddying circulation could transport suspend settled sediments from eastern shoreline towards the port entrance and its access channel. The results of this paper are mostly based on the study of current patterns around the port in the storm conditions incorporate with the identification of sediment sources.

An Experimental Testing of Fillet Welded Specimens

2015 ◽  
Vol 752-753 ◽  
pp. 412-417 ◽  
Author(s):  
Martin Krejsa ◽  
Jiri Brozovsky ◽  
David Mikolasek ◽  
Premysl Parenica ◽  
Libor Zidek ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Stress Analysis ◽  
Numerical Models ◽  
Experimental Testing ◽  
Fem Analysis ◽  
Experimental Tests ◽  
Strength Characteristics ◽  
Fillet Welds ◽  
Commercial Software

The paper describes the experimental tests of steel bearing elements, which were aimed at obtaining material, geometric and strength characteristics of the fillet welds. Preparation of experiment consisted in defining of numerical models of tested samples using FEM analysis and the commercial software ANSYS. Data obtained from described experimental tests are necessary for further numerical modelling of stress analysis of steel structural supporting elements.

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