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Mramor K.,Cobik | Vertnik R.,Store Steel | Vertnik R.,University of Nova Gorica | Sarler B.,University of Nova Gorica | Sarler B.,Slovenian Institute of Metals And Technology
Engineering Analysis with Boundary Elements | Year: 2014

The purpose of the present paper is to extend the use of a novel meshless Local Radial Basis Function Collocation Method (LRBFCM) for solving the two-dimensional, steady, laminar flow over a backward facing step under the influence of the Lorentz force. The incompressible Navier-Stokes equations are under the influence of predetermined static magnetic field numerically solved on a non-uniform node arrangement. In the numerical procedure, local collocation and Multiquadric Radial Basis Functions (MQ RBF) are used on five-nodded subdomains. The coupling between the pressure and the velocity is made by using Fractional Step Method (FSM). The considered problem is calculated for Reynolds numbers (Re) ranging from 300 to 800, Hartman numbers (Ha) ranging from 0 to 100, and for low magnetic Rem number. The numerical results demonstrate excellent agreement with previously published data, obtained with the classical numerical methods, such as Finite Volume Method (FVM) and Finite Element Method (FEM). Simplicity of the numerical implementation, accuracy and the absence of the polygonalisation are the main advantages of the LRBFCM. © 2014 Elsevier Ltd. All rights reserved.

Zagar K.,Cosylab D.d. | Bokal D.,Cosylab D.d. | Strnisa K.,Cosylab D.d. | Gasperin M.,University of West Bohemia | And 3 more authors.
IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference | Year: 2013

In Accelerator Driven Systems, high availability of the accelerator is one of its key requirements. Fortunately, not every beam trip is necessarily a failure. For example, in the proposed MYRRHA transmuter, absence of the beam for less than 3 seconds is still deemed acceptable. Predictive diagnostics strives to predict where a failure is likely to occur, so that a mitigating action can be taken in a more controlled manner, thus preventing failure of other components while exactly pinpointing the component that is about to fail. One approach to predictive diagnostics is to analyze process variables that quantify inputs and outputs of components as archived by the accelerator's distributed control system. By observing trends in their values an impending fault can be predicted. In addition, sensors measuring e.g., vibration, temperature or noise can be attached to critical components. Copyright © 2013 by JACoW.

Mramor K.,Cobik | Vertnik R.,Store Steel | Vertnik R.,University of Nova Gorica | Sarler B.,Cobik | And 2 more authors.
Computers, Materials and Continua | Year: 2013

This paper explores the application of Local Radial Basis Function Collocation Method (LRBFCM) [Šarler and Vertnik (2006)] for solution of Newtonian incompressible 2D fluid flow for a lid driven cavity problem [Ghia, Ghia, and Shin (1982)] in primitive variables. The involved velocity and pressure fields are represented on overlapping five-noded sub-domains through collocation by using Radial Basis Functions (RBF). The required first and second derivatives of the fields are calculated from the respective derivatives of the RBF's. The momentum equation is solved through explicit time stepping. The method is alternatively structured with multiquadrics and inverse multiquadrics RBF's. In addition, two different approaches are used for pressure velocity coupling (Fractional Step Method (FSM) [Chorin (1968)] and Artificial Compressibility Method (ACM) [Chorin (1967)] with Characteristic Based Split (CBS) [Zienkiewicz and Codina (1995); Zienkiewicz, Morgan, Sai, Codina and Vasquez (1995)]). The method is tested for several low and intermediate Reynolds numbers (100, 400, 1000 and 3200) and node arrangements (41x41, 81x81, 101x101, 129x129). The original contribution of the paper represents extension of the LRBFCM to Reynolds number beyond 400 and assessment of the method for two different types of RBFs and two different types of pressure-velocity couplings. The obtained numerical results, in terms of mid-plane velocities, are in a good agreement with the data calculated in several reference publications and by commercial code. Both RBF's used give approximately the same results. Both pressure-velocity coupling methods give approximately the same results, however the FSM turns out to be slightly more efficient. The advantages of the method are simplicity, accuracy and straightforward applicability in non-uniform node arrangements. Copyright © 2013 Tech Science Press.

Mramor K.,Cobik | Vertnik R.,Store Steel | Sarler B.,Cobik | Sarler B.,IMT Inc
CMES - Computer Modeling in Engineering and Sciences | Year: 2013

The purpose of the present paper is to extend and explore the application of a novel meshless Local Radial Basis Function Collocation Method (LRBFCM) in solution of a steady, laminar, natural convection flow, influenced by magnetic field. The problem is defined by coupled mass, momentum, energy and induction equations that are solved in two dimensions by using local collocation with multiquadrics radial basis functions on an overlapping five nodded subdomains and explicit time-stepping. The fractional step method is used to couple the pressure and velocity fields. The considered problem is calculated in a square cavity with two insulated horizontal and two differentially heated vertical walls with magnetic field applied in the horizontal direction. Numerical predictions are calculated for different Grashof numbers, ranging from 10 4 to 106, and Hartman numbers, ranging from 0 to 100, at Prandtl numbers 0.71 and 0.14. The results of the method are compared to predictions, obtained by other numerical methods, including FLUENT [Fluent (2003)]. Good agreement has been achieved. The LRBFCM has been used in this kind of problems for the first time. The main advantage of the method is its simple numerical implementation and no need for polygonisation. Copyright © 2013 Tech Science Press.

Dedic J.,Cobik | Zagar K.,Cobik | Soderqvist A.,Cosylab | Claesson N.,Cosylab | And 2 more authors.
IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference | Year: 2013

This paper presents a Field Programmable Gate Array (FPGA) development workflow for custom hardware as part of an accelerator control systems. The workflow is narrowed down to three equally important parts: requirements analysis, implementation and testing. Each part is presented with milestones and guidelines, which addresses subjects such as knowledge alignment and development standards. These are presented and have been proven to increase efficiency and quality of control systems. Copyright © 2013 by JACoW.

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