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Article
Publication date: 11 May 2010

Fikri Serdar Gokhan and Gunes Yilmaz

The purpose of this paper is to demonstrate an effective and faster numerical solution for nonlinear‐coupled differential equations describing fiber amplifiers which have…

Abstract

Purpose

The purpose of this paper is to demonstrate an effective and faster numerical solution for nonlinear‐coupled differential equations describing fiber amplifiers which have no explicit solution. MATLAB boundary value problem (BVP) solver of bvp6c function is addressed for the solution.

Design/methodology/approach

Coding method with the bvp6c is introduced, signal evolution, threshold calculation method is introduced, gain and noise figure are plotted and superiority of the bvp6c solver is compared with the Newton‐Raphson method.

Findings

bvp6c function appears to be an effective tool for the solution fiber amplifier equations and can be used for different pump configurations of BFAs and RFAs. The excellent agreement between the proposed and reported results shows the reliability of the proposed threshold power calculation method.

Research limitations/implications

The paper eases the work of the fiber optic research community, who suffer from two point BVPs. Moreover, the stiffness of the signal evolution which is faced with high pump powers and/or long fiber lengths can be solved with continuation. This superiority of the solver can be used to overcome any stiff changes of the signals for the future studies.

Practical implications

The main outcome of this paper is the numerically calculation of the threshold values of fiber amplifiers without the necessity of the experiment. The robustness improvement of the solution is that the solver is able to solve the equations even with the poor guess values and the solution can be obtained without the necessity of analytical Jacobian matrix.

Originality/value

MATLAB bvp6c solver has proven to be effective for the numerical solution of nonlinear‐coupled intensity differential equations describing fiber amplifiers with two‐point boundary values. Beside the signal evolution, thresholds of Brillouin and Raman fiber amplifiers can also be calculated by using the proposed solver. This is a notable and promising improvement of the paper, at least from a fiber optic amplifier designer point of view.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 22 June 2020

Naveed Imran, Maryiam Javed, Muhammad Sohail, S. Farooq and Mubashir Qayyum

Naturally, all the materials are not viscous (i.e. milk, mayonnaise, blood, vaccines, syrups, cosmetics, oil reservoirs, paints, etc.). Here present analysis focuses on…

Abstract

Purpose

Naturally, all the materials are not viscous (i.e. milk, mayonnaise, blood, vaccines, syrups, cosmetics, oil reservoirs, paints, etc.). Here present analysis focuses on the usage of non-Newtonian fluid rheological properties enhancing, damping tools, protection apparatus individuals and in various distinct mechanical procedures. Industrial applications of non-Newtonian liquids include minimum friction, reduction in oil-pipeline friction, scale-up, flow tracers and in several others. The peristaltic mechanism is used as a non-Newtonian material carrier here. This mechanism occurs because of continuous symmetrical and asymmetrical propulsion of smooth channel walls. Peristalsis is a very significant mechanism for carrying drugs and other materials during sensitive diseases treatments.

Design/methodology/approach

Keeping in mind the considered problem assumptions (Rabinowitsch fluid model, thermal Grashof number, Prandtl number, density Grashof number, wall properties, etc.), it is found that the modeled equations are coupled and nonlinear. Thus here, analytical results are quite challenging to acquire and very limited to extremely venerated circumstances unsettled to their nonlinearity. Hence various developments found in computing proficiencies, numerical procedures that provides accurate, stable and satisfying solutions for non-Newtonian material flows exclusively in complex dimensions play a significant role. Here BVP4C numerical technique is developed to evaluate the nonlinear coupled system of equations with appropriate boundary constraints.

Findings

Due to convectively heated surface fluid between the walls having a small temperature. Sherwood and Nusselt numbers both deduce for fixed radiation values and different Rabinowitsch fluid quantity. Skin friction is maximum in the case of Newtonian, while minimum in case of dilatant model and pseudoplastic models. The influence of numerous parameters associated with flow problems such as thermal Grashof number, density Grashof number, Hartman number, Brownian motion, thermophoresis motion factor and slip parameters are also explored in detail and plotted for concentration profile, temperature distribution and velocity. From this analysis, it is concluded that velocity escalates for larger

Originality/value

The work reported in this manuscript has not been investigated so far by any researcher.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 4 July 2016

Bahram Tarvirdizadeh, Khalil Alipour and Alireza Hadi

– The purpose of this paper is to focus on an online closed-loop (CL) approach for performing dynamic object manipulation (DOM) by a flexible link manipulator.

Abstract

Purpose

The purpose of this paper is to focus on an online closed-loop (CL) approach for performing dynamic object manipulation (DOM) by a flexible link manipulator.

Design/methodology/approach

Toward above goal, a neural network and optimal control are integrated in a closed-loop structure, to achieve a robust control for online DOM applications. Additionally, an elegant novel numerical solution method will be developed which can handle the split boundary value problem resulted from DOM mission requirements for a wide range of boundary conditions.

Findings

The obtained simulation results reveal the effectiveness of both proposed innovative numerical solution technique and control structure for online object manipulation purposes using flexible manipulators.

Originality/value

The object manipulation problem has previously been studied, however, for the first time its accomplishment by flexible link manipulators was addressed just in offline form considering an open-loop control structure (Tarvirdizadeh and Yousefi-Koma, 2012). As an extension of Tarvirdizadeh and Yousefi-Koma (2012), the current research, consequently, focusses on a numerical solution and a CL approach for performing DOM by a flexible link manipulator.

Details

Engineering Computations, vol. 33 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 8 March 2011

Fikri Serdar Gokhan and Gunes Yilmaz

The purpose of this paper is to demonstrate an effective and robust numerical solution for Raman fiber amplifier (RFA) equations which have no explicit solution. MATLAB…

Abstract

Purpose

The purpose of this paper is to demonstrate an effective and robust numerical solution for Raman fiber amplifier (RFA) equations which have no explicit solution. MATLAB BVP solvers are addressed for the solution.

Design/methodology/approach

The continuation method proposed for the solution of RFA equations using MATLAB BVP solvers is explained. Scripts for improving the power values at the boundaries with continuation, extending fiber length with continuation and calculation of the analytical partial derivatives using the MATLAB Symbolic toolbox are introduced. Comparisons among the different MATLAB BVP solvers have been made. Using the continuation method, signal evolutions for different kinds of RFA amplifier configurations are plotted.

Findings

The paper finds that MATLAB BVP solver with the continuation method can be used in the design of various kinds of RFAs for high powers/long gain fiber spans.

Research limitations/implications

The paper will assist the fiber optic research community who suffer from two or more point boundary‐value problems. Moreover, the stiffness of the signal evolution which is faced with high pump powers and/or long fiber lengths can be solved with continuation. This superiority of the solver can be used to overcome any stiff changes of the signals for future studies.

Practical implications

The increased research interests and practical demands for RFAs have been calling for reasonable and efficient means for the performance evaluation of RFAs before the real amplifiers are fabricated. The solution method presented in this paper will be an efficient means for the solution of this issue.

Originality/value

MATLAB BVP solvers have been proven to be effective for the numerical solution of RFAs with multiple pumps and signal waves. Using the continuation method, in a distributed RFA with ten pump sources, 2,400 mW total input pump power is achieved. The improvement of the total power is about 1.4 times compared with those of the previously reported methods. Using the MATLAB BVP solvers, total power/fiber span can be improved further using the continuation process with the cost of computational time. This is a notable and promising improvement from a RFA designer's point of view.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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