Monday, February 1. 2021
S.A. Khuri1, I. Louhichi, A. Sayfy
Department of Mathematics and Statistics, American University of Sharjah - UAE
Received 14 January, 2019; accepted in revised form 26 January, 2021
Abstract: In this article, we study a fixed point iteration scheme that involves the Green’s function for the numerical solution of a larger class of fourth order boundary value problems (BVPs). The scheme enjoys important features such as its high accuracy, reliability, and fast convergence. We analyze and prove convergence of the iterative procedure using the contraction principle. Several numerical examples of fourth order boundary value problems are used to test the proposed method. The numerical results clarify very good agreement with the exact solution and superiority of this approach when compared with other numerical results that exist in the literature. Furthermore, the method requires less CPU time than other techniques.
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Saturday, December 12. 2020
Research of Integrated Passive Methods of Heat Dissipation Intensification to Improve the Efficiency of Gas-Dynamic Temperature Stratification
Е.V. Tsvetova, V.N. Kovalnogov, R.V. Fedorov
Department of Heat and Power Engineering, Ulyanovsk State Technical University, Severny Venets str. 32, Ulyanovsk, 432027, Russia
© European Society of Computational Methods in Sciences and Engineering
Keywords: numerical simulation, gas-dynamic temperature stratification, dispersion flow, heat transfer
coefficient, developed surfaces
Mathematics Subject Classification: 65R20 Numerical methods for integral equations
Received: 04/09/2020, Revised: 20/10/2020, Accepted: 05/12/2020
Abstract: A possibility was analyzed to increase the efficiency of the gas-dynamic temperature stratification process through the use of complex passive methods of heat transfer intensification: developed surfaces - longitudinal fins on the heat transfer surface in the subsonic flow path; additives to the gas flow of the disperse phase with a twisting flow.
PACS: 02.60.Cb Numerical simulation; solution of equations
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Saturday, December 12. 2020
Numerical Simulation and Investigation of the Influence of the Characteristics of the Building Envelope on Energy Efficiency and Energy Saving Potential
Yu.E. Chamchiyan, V.N. Kovalnogov, R.V. Fedorov
Department of Heat and Power Engineering, Ulyanovsk State Technical University, Severny Venets str. 32, Ulyanovsk, 432027, Russia
Received: 03/09/2020, Revised: 15/10/2020, Accepted: 08/12/2020
Abstract: The heat engineering characteristics of external enclosing structures and their influence on the microclimate of the building are analyzed. Potential spheres in the field of providing microclimate for energy saving are considered. The potential for savings in the implementation of automated regulation of microclimate systems is presented.
© European Society of Computational Methods in Sciences and Engineering
Keywords: numerical simulation, numerical methods, energy efficiency, energy saving, microclimate.
Mathematics Subject Classification: 65R20 Numerical methods for integral equations
PACS: 02.60.Cb Numerical simulation; solution of equations
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Saturday, December 12. 2020
Influence of the Air Swirling Speed on the Processes of Joint Combustion of the Fuel-Air Mixture in the Active Combustion Zone of Power Plants
R.V. Fedorov, A.V. Chukalin, V.N. Kovalnogov, U.J. Mizher, M.M. Zamaleev
Department of Heat and Power Engineering,
Ulyanovsk State Technical University, Severny Venets str. 32, Ulyanovsk, 432027, Russia
Received: 01/09/2020, Revised: 15/10/2020, Accepted: 07/12/2020
Abstract: The search for new solutions in the field of energy, preventing negative impact on the environment, is one of the priority tasks for modern society. It is natural gas that has a stable position in the demand of the UES of Russia for fossil fuel. One of the promising areas is the use of biogas as a source of thermal energy for power plants. It has been established that the main difference between biogas and natural gas, which affects the density, calorific value, and speed of flame propagation, is caused by the presence of more than 30% carbon dioxide in its composition. Combined combustion of natural gas and biogas, subject to good mixing due to the tangentially swirling apparatus of the fuel-air mixture, can increase the stability of biogas combustion, reduce the maximum adiabatic temperature in the zone of active combustion of power boilers of TPPs, which in turn will lead to a decrease in the content of NOx, CO2 in products combustion. For the combustion of biogas at the power plants in operation at TPPs of the UES of Russia, it is important to carry out, on the basis of the theoretical data obtained on the effective combustion modes of fuels, the technical re-equipment of the burners. The paper presents a turbulence model k – ε RNG, which makes it possible to simulate the combustion of natural gas and biogas during tangential swirling of the air-fuel mixture. The qualitative characteristics of biogas, the quantitative content of NOx, CO2 in the combustion products, the temperature distribution in the zone of active combustion of fuel combinations - natural gas, biogas, natural gas / biogas is presented.
© European Society of Computational Methods in Sciences and Engineering
Keywords: Numerical simulation, modeling, biogas, co-combustion, efficiency, emission reduction
Mathematics Subject Classification: 65R20 Numerical methods for integral equations
PACS: 02.60.Cb Numerical simulation; solution of equations
Tuesday, December 8. 2020
Effectiveness of the Probabilistic Assessment to Analyse of the Tall Building Safety using FE Method
J. Kralik, J. Kralik, jr. and P. Rosko
Faculty of Civil Engineering, Slovak University of Technology in Bratislava, 810 05 Bratislava, Slovakia
and
Centre of Mechanics and Structural Dynamics 1010 Vienna University of Technology Vienna, Austria
Received 01/03/2020, Revised 21/07/2020, Accepted 30/10/2020
Abstract: This paper describes some experiences from the deterministic and probabilistic analysis of building structure reliability and safety. There are presented the methods and requirements of Eurocode EN 1990, standard ISO 2394 and JCSS. On the example of the probability analysis of the reliability of the tall buildings is demonstrated the affectivity of the probability design of structures using FE Method.
© European Society of Computational Methods in Sciences and Engineering
Keywords: Extreme environment effect, earthquake, nonlinearity, probability, sensitivity, RSM, ANSYS
Mathematics Subject Classification: 00A69, 49Mxx
Tuesday, December 8. 2020
Probabilistic Assessment to Analyze of Steel Hall Collapse due to Extreme Wind Impact
J. Kralik and J. Kralik, jr.
Department of Structural Mechanics,
Faculty of Civil Engineering,
Slovak University of Technology in Bratislava,
810 05 Bratislava, Slovakia
Received 28/02/2020, Revised 21/07/2020, Accepted 28/10/2020 Abstract: Engineering structures are designed to resist all expected loadings without failure. However, structural failures do happen occasionally, mainly due to inadequate design and construction, especially for extreme loads. The main aim of this contribution is to find out the maximum load carrying capacity of the steel frame. Account is taken of nonlinear material behavior and geometry of member, in combination of the stability analysis.
© European Society of Computational Methods in Sciences and Engineering
Keywords: Extreme wind, nonlinearity, probability, sensitivity, NPP, RSM, FEM, ANSYS
Mathematics Subject Classification: 00A69, 49Mxx
Tuesday, November 17. 2020
Numerical Analysis of the One-Dimensional Nonlinear Boundary Value Problem that Modeling an Electrostatic NEMS by Two-Sided Approximations Method
O. Konchakovska, M. Sidorov
Department of Applied Mathematics, Faculty of Information and Analytical Technologies and Managment,
Kharkiv National University of Radio Electronics,
61166, Kharkiv, Ukraine
Received 17 May, 2020; accepted in revised form 10 November, 2020
Abstract: The problem of numerical analysis of a nanoelectromechanical system, whose mathematical model is the first boundary value problem for a nonlinear one-dimensional elliptic equation, has been considered. An algorithm for obtaining two-sided approximations to a unique positive solution of the problem has been constructed using the method of successive approximations. The work of the proposed method is demonstrated by a series of computational experiments.
c⃝ 2020 European Society of Computational Methods in Sciences and Engineering
Keywords: two-sided approach method, Green’s functions method, strongly invariant cone
segment, heterotone operator, nanoelectromechanical system
Mathematics Subject Classification: 34B15; 34B18
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Monday, September 14. 2020
A New Conjugate Gradient Method with Descent Properties and its Application to Regression analysis
Ibrahim Mohammed Sulaiman1, Mustafa Mamat1*
1Faculty of Informatics and Computing, Universiti Sultan Zainal Abidin, 21300 Terengganu, Malaysia
corresponding author: *must@unisza.edu.my
sulaimanib@unisza.edu.my
Submitted 24/07/2019, Revised 13/01/2020, 2nd revised: 11/06/2020, accepted: 09/09/2020
Abstract: The area of unconstrained optimization has been enjoying vivid growth recently, with significant progress on numerical innovative techniques. The classical technique for obtaining the solution of this problem is the Conjugate Gradient (CG) scheme, due to its rapid convergence rate with low memory requirements. However, recent variations of CG methods are complicated and computationally expensive. This paper presents a new and efficient CG parameter with descent condition for solving optimization problems. The convergence result of this method is established under exact and inexact line search. The proposed method is applied to real-life problems in regression analysis. Numerical results have been reported to illustrate the efficiency and robustness of the proposed method.
© European Society of Computational Methods in Sciences and Engineering
Keywords: Optimization; exact line search; global convergence; conjugate gradient method;
Mathematics Subject Classification: 90C53; 65K05
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Tuesday, August 25. 2020
Numerical approximations of the Keyfitz-Kranzer type models by using entropy stable schemes
Carlos A. Vega1
Departmento de Matem´aticas y Estadıstica,
Universidad del Norte,
Km 5 Via Puerto Colombia Barranquilla, Colombia.
Sonia Valbuena
Grupo GIHEM,
Universidad del Atl´antico,
Km 7 Via Puerto Colombia Barranquilla, Colombia.
Abstract: Numerical simulations for the Keyfitz-Kranzer system of equations are developed by using high-order entropy stable schemes proposed by Fjordholm et. al. [Arbitrary high-order essentially non-oscillatory entropy stable schemes for systems of conservation laws, SIAM J. Numer. Anal., 50, 544-573 (2012)]. Since existence of entropy pairs is an important ingredient to this approach, they are described in details. Numerical experiments include errors and convergence rates to illustrate the performance of the schemes.
c 2020 European Society of Computational Methods in Sciences and Engineering
Keywords: Conservation laws, Keyfitz-Kranzer system, entropy conservative flux, entropy stable scheme.
Mathematics Subject Classification: 35L65, 35L45, 35L67, 58J45, 65M06
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Wednesday, May 6. 2020
Finite Integration Method Using Chebyshev Expansion for
Solving Nonlinear Poisson Equations on Irregular Domains
A. Duangpan1 and R. Boonklurb2
1,2Department of Mathematics and Computer Science, Faculty of Science,
Chulalongkorn University, Bangkok 10330, Thailand
Received 27 March, 2019; accepted in revised form 28 April, 2020
Abstract: Several boundary value problems are de ned on complex shaped domains, such as pentagonal, circular, L-shaped, butter y, peanut-shaped and elliptic domains. These irregular domains give diculty in term of solving both analytically and numerically. This paper devises the nite integration method via Chebyshev polynomials (FIM-CBS) to deduce the ecient numerical scheme for solving two-dimensional nonlinear Poisson equations over these irregular domains with the discretization through Chebyshev nodes. The demonstrative numerical examples are provided. The numerical solutions by the FIM-CBS are compared with the analytical solutions. The results show that the proposed method is very e ective and accurate with a small number of computational nodes.
c 2020 European Society of Computational Methods in Sciences and Engineering
Keywords: nite integration method, Chebyshev polynomial, nonlinear Poisson equation, irregular domain
Mathematics Subject Classi cation: 65D30, 65M50, 65N30
Thursday, March 26. 2020
SEMI-EMPIRICAL COMPUTATIONAL METHOD FOR STUDYING THE DIFFUSION OF MOISTURE AND GENERATOR GASES IN THE CAPILLARY-POROUS SPACE OF REPRESENTATIVE BIOFUELS
T.V. Karpukhina1, V.N. Kovalnogov1,2, M.S. Boyarkin1
1Department of Heat-and-Power Engineering, Faculty of Power Engineering, Ulyanovsk State Technical University, SevernyVenets Street 32, 432027 Ulyanovsk, Russian Federation
2Scientific and Educational Center "Digital Industry", South Ural State University, 76 Lenin Ave., 454080 Chelyabinsk, Russian Federation
Received 10 March, 2020; Accepted in revised form 23 March, 2020
Abstract
The complex of issues related to the mathematical modeling of heat-and-mass transfer of moisture and gas in the capillary-porous space of solid biofuel cells is discussed. This is the theoretical basis for developing of biofuel enrichment technologies which include heating with simultaneous saturation of the capillary-porous space by the synthesis gas and the combustible components of the recycle gas that in complex contributes the most complete combustion of cells and improve the fuel efficiency and environmental friendliness of the boiler plant. The mathematical model defining the kinetics of heat and humidity conditions and saturation of biofuel cellsis given and discussed.
Keywords: diffusion, capillary-porous space, heat-and-humidity state, modeling,enrichment technology.
c 2020 European Society of Computational Methods in Sciences and Engineering
Tuesday, January 28. 2020
Structure preserving algorithms for simulation of linearly damped acoustic systems
Vasileios Chatziioannou1
1Department of Music Acoustics, University of Music and Performing Arts Vienna, Austria
Received: 22 August 2017 ; Accepted in revised form: 22 January 2020
Abstract: Energy methods for constructing time-stepping algorithms are of increased in- terest in application to nonlinear problems, since numerical stability can be inferred from the conservation of the system energy. Alternatively, symplectic integrators may be constructed that preserve the symplectic form of the system. This methodology has been established for Hamiltonian systems, with numerous applications in engineering problems. In this paper an extension of such methods to non-conservative acoustic systems is presented. Discrete conservation laws, equivalent to that of energy-conserving schemes, are derived for systems with linear damping, incorporating the action of external forces. Furthermore the evolution of the symplectic structure is analysed in the continuous and the discrete case. Existing methods are examined and novel methods are designed using a lumped oscillator as an elemental model. The proposed methodology is extended to the
case of distributed systems and exemplified through a case study of a vibrating string bouncing against a rigid obstacle.
c 2019 European Society of Computational Methods in Sciences and Engineering
Keywords: Energy conservation, symplectic form, mechanical integrator, linear damping
Mathematics Subject Classification: 65M06, 65P10, 65Z05
Monday, December 2. 2019
Radiation-Resistant Robotic Complex: Hardware, Software And Mathematical Concepts
E.M. Chavkin1, A.N. Fomin1, V.V. Prikhodko1, A.A. Sobolev1, A.V.Zhukov1, P.E. Kapustin1,
V.E. Kiryukhin1, D.S. Lavygin1, V.V. Levshchanov1, S.V. Pavlov2, V.P. Smirnov2,
V.V. Svetukhin3
1S.P. Kapitsa Technological Research Institute of Ulyanovsk State University, Ulyanovsk, Russia, vp@kapitsa.tech
2 Sosny Research and Development Company, Dimitrovgrad, Ulyanovsk region, Russia
3 SMC «Technological Center», Zelenograd, Moscow, Russia.
Received: 12 November 2019; Accepted in revised form: 29 November 2019
Abstract.
The results of developing a radiation-hardened robotic complex to work in hot cells at nuclear industry facilities are presented. For each constituting element of the complex – arobotic manipulator, a control device with force feedback, control software – a detailed description is given.Special attention is paid to the mathematical basis of the manual control mode implemented by means of an original 6-DoF joystick.Further development of the control software made it possible to create a training simulator, the software part of which is identical to that used for the robotic arm control. The simulator hardware consists of VR equipment and the 6-DoF joystick.
Keywords: robotic complex, manipulator, control device, force feedback, joystick, control algorithms, mathematical basis, radiation-protected chamber, hot cell, training simulator, virtual reality, VR, control software.
Sunday, July 28. 2019
Numerical Analysis of Bearing Capacity of Soil
S. Harabinova, E. Panulinova, E. Kormanikova
Institute of Structural Engineering,
Faculty of Civil Engineering,
Technical University of Kosice,
042 00 Kosice, Slovakia
Received 31 January, 2018; accepted in revised form 23 July, 2019
Abstract: The strength of soil and the bearing capacity are a keys design parameters in designing foundations and other earth structures. Proper interpretation of shear strength parameters and the application to bearing capacity problems are presented and evaluated in this paper. Theory of bearing capacity is developed, on the basis of plastic theory, by changing the shear strength parameters for cohesive soil. In foundation design, the capacity of the foundation to support footing load is given by the soil´s bearing capacity, which is a function of its strength parameters. The maximum pressure, that the soil can support at foundation level without failure depends on the bearing capacity of soil. The bearing capacity of soil in purely cohesive material changes linear with cohesion resistance. However, the bearing capacity
changes exponential with the angle of internal friction of soil. By comparing obtained results it was founded, that change the angle of internal friction in cohesive soils have more effect on increasing bearing capacity.
© European Society of Computational Methods in Sciences and Engineering
Keywords: bearing capacity, foundation, failure, strength of soil, cohesive soil, numerical analysis
Mathematics SubjectClassification: 00A69, 49Mxx
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Friday, July 19. 2019
Evaluation of Turbulence Models for Flow Over a Thermally Loaded Hill
Ivan Kološ1, a), Lenka Lausová1, b) and Vladimíra Michalcová1, c)
1VŠB - Technical University of Ostrava, Faculty of Civil Engineering, L. Podéště 1875/17, 708 33 Ostrava-Poruba, Czech Republic
a)Corresponding author: ivan.kolos@vsb.cz, b)lenka.lausova@vsb.cz, c)vladimira.michalcova@vsb.cz
Abstract. CFD models are widely used for modelling of flow over objects, as they provide very good results of the turbulence characteristics of the flow. The aim of the paper is to analyse suitability of selected numerical models of flow in an unstable temperature-stratified boundary layer over the temperature-loaded object. A numerical analysis has been carried out using four turbulence models: Transition SST κ-ω model, LES model, SAS model and DES model. The velocity and temperature fields of a single temperature loaded hill are evaluated in horizontal profiles at four levels of the hill on both, the windward and leeward sides.
© European Society of Computational Methods in Sciences and Engineering
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