Solution of Harmonic Engineering Problems Using Equilibrated Basis Functions in a Weak Weighted Residual Approach in Polar Coordinates

Document Type : Research Paper

Authors

1 M.Sc. student, Department of Civil Engineering, Faculty of Civil Engineering, Isfahan University of Technology, Isfahan, Iran

2 Assistant Professor, Department of Civil Engineering, Faculty of Civil Engineering, Isfahan University of Technology, Isfahan, Iran

3 Professor, Department of Civil Engineering, Faculty of Civil Engineering, Isfahan University of Technology, Isfahan, Iran

Abstract

In solution of many engineering problems, including problems related to flow modeling in civil engineering, the use of mesh-less methods is common due to the provision of the potential field along with continuous and accurate velocity. Methods using basis functions are among the mesh-less techniques that use a set of basic functions that necessarily satisfy the homogeneous form of the equation, which is a major limitation. The equilibrated basis functions are capable of dissolving that defect by approximately satisfying the homogeneous equation in the form of a weighted residual integration, while still providing the continuity of the solution function and its derivatives throughout the domain. In the present study the weak weighted residual form, in which lower derivation orders appear than the strong form, will be implemented. The relations are expanded in a polar coordinate system. To demonstrate the efficiency of the method in engineering problems, the potential flow around a cylindrical barrier will be examined.

Keywords


[1]-Trefftz, E., 1926, Ein Gegenstück zum ritzschen Verfahren, Proceedings of 2nd International Congress on Applied Mechanics, Zurich, pp.131-137.
[2]- Kupradze, V. D., and Aleksidze, M. A., 1964, The method of functional equations for the approximate solution of certain boundary value problems, U.S.S.R. Computational Mathematics and Mathematical Physics, 4, pp.82-126.
[3]-Cheng, A. H. D., and Cheng, D. T., 2005, Heritage and early history of the boundary element method, Engineering Analysis with Boundary Elements, 29, pp.268-302.
[4]- Brebbia, C. A., 1978, The boundary element method for engineers, Halstead Press, New York.
[5]-Broomhead, D. S., and Lowe, D., 1988, Multivariable functional interpolation and adaptive network”, Complex Systems, 2, pp.321-355.
[6]- Buhmann, M. D., 2000, Radial Basis Functions, Acta Numerica, Cambridge Press, pp.1-38.
[7]- سقراطی، س، 1383، استفاده از توابع پایه هموار در حل برخی معادلات دیفرانسیل حاکم بر مسائل مکانیک جامدات، پایان نامه کارشناسی ارشد، دانشکده مهندسی عمران، دانشگاه صنعتی اصفهان.    
[8]- مسیبی، ف.، 1389، حل مسائل مکانیک جامدات در محیط های محدود و نامحدود با استفاده از روش های نیمه تحلیلی و اجزا محدود، رساله دکتری، دانشکده مهندسی عمران، دانشگاه صنعتی اصفهان.
[9]- نورمحمدی، ن.، 1390، حل مسائل مکانیک جامدات با استفاده از توابع پایه تعمیم یافته، پایان نامه کارشناسی ارشد، دانشکده مهندسی عمران، دانشگاه صنعتی اصفهان.        
[10]-Noormohammadi, N., and Boroomand, B., 2014, A fictitious domain method using equilibrated basis functions for harmonic and bi-harmonic problems in physics, Journal of Computational Physics, 272, pp. 189-217.