TASK Quarterly   Scientific Bulletin of the Centre of Informatics - Tricity Academic Supercomputer & networK   ISSN 1428-6394

Volume 20, Number 1, 2016


Contents:



Abstracts:

  • Leonardo Pasini and Samuele Sabbatini Urban Flows Simulator Based on Complex System of Queues: Procedures for Simulator Generation

    In a previous work [1], we have defined an object library that allows the building of architectural models of urban traffi systems. In this work we illustrate the procedures that enable us to produce a system simulator starting from the architectural model of an urban vehicular traffi system.

  • Jaroslav Pyanylo and Petro Vavrychuk Determining the Gas-Water Contact Moving Boundary in Underground Gas Storage Operation

    We considered the characteristics of key technological objects involved in gas storage. Mathematical models of groups of hydraulically related objects (system mathematical models) are constructed and described. Problems are set and examples of application of analytical and numerical methods for their solution are provided.

  • Sergiy Yershov, Anton Derevyanko, Viktor Yakovlev and Maria Gryzun Numerical Simulation of 3D Flow in VKI-Genoa Turbine Cascade Including Laminar-Turbulent Transition

    This study presents a numerical simulation of a 3D viscous flow in the VKI-Genoa cascade taking into account the laminar-turbulent transition. The numerical simulation is performed using the Reynolds-averaged Navier-Stokes equations and the two-equation k-ω SST turbulence model. The algebraic Production Term Modification model is used for modeling the laminar-turbulent transition. Computations of both fully turbulent and transitional flows are carried out. The Mach number contours, the turbulence kinetic energy, the entropy function as well as the limiting streamlines are presented. Our numerical results demonstrate the influence of the laminar-turbulent transition on the secondary flow pattern. The comparison between the present computational results and the existing experimental and numerical data shows that the proposed approach reflects suffiiently the physics of the laminar-turbulent transition in turbine cascades.

  • Tadeusz Jankowski Fractional Problems with Right-Handed Riemann-Liouville Fractional Derivatives

    In this paper, we investigate the existence of solutions for advanced fractional differential equations containing the right-handed Riemann-Liouville fractional derivative both with nonlinear boundary conditions and also with initial conditions given at the end point T of interval [0,T ]. We use both the method of successive approximations, the Banach fixed point theorem and the monotone iterative technique, as well. Linear problems are also discussed. A few examples illustrate the results.

  • Tadeusz Jankowski Multiple Solutions to Third-Order Differential Equations with Derivative Dependence and Deviating Arguments

    In this paper, we give some new results for multiplicity of positive (nonnegative) solutions for third-order differential equations with derivative dependence, deviating arguments and Stieltjes integral boundary conditions. We discuss our problem with advanced argument α and arbitrary β ∈ C([0,1],[0,1]), see problem (2). It means that argument β can change the ¯ ¯ character on [0,1], so β can be delayed in some set J ⊂ [0,1] and advanced in [0,1] \ J. Four examples illustrate the main results.

  • Tadeusz Jankowski Successive Iterative Method for Higher-Order Fractional Differential Equations Involving Stieltjes Integral Boundary Conditions

    In this paper, the existence of positive solutions to fractional differential equations with delayed arguments and Stieltjes integral boundary conditions is discussed. The convergence of successive iterative method of solving such problems is investigated. This allows us to improve some recent works. Some numerical examples illustrate the results.