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Article Citation - Scopus: 2A New Formulation for the Boundary Element Analysis of Heat Conduction Problems With Nonlinear Boundary Conditions;(Turk Isı Bilimi ve Teknigi Dernegi, 2019) Baranoğlu,B.An effective numerical method based on the boundary element formulation is presented to solve heat conduction equations which are governed by the Fourier equation, with nonlinear boundary conditions on one or more sections of the prescribed boundary. The solution involves the manipulation of the system matrices of the boundary element method and obtaining a smaller ranked matrix equation in which the unknown is only the temperature difference over the nonlinear boundary condition region. This way, the iterations to deal with the nonlinear conditions are performed faster. After finding the solution over the nonlinear boundary condition region, the solution over the entire boundary is obtained as a post-process through a prescribed relation. An example with a proven exact solution is employed to assess the results. © 2019 TIBTD Printed in TurkeyArticle Citation - WoS: 4Citation - Scopus: 4A Frequency Domain Boundary Element Formulation for Dynamic Interaction Problems in Poroviscoelastic Media(Springer, 2014) Argeso, Hakan; Mengi, YalcinA unified formulation is presented, based on the boundary element method, to perform the interaction analysis for the problems involving poroviscoelastic media. The proposed formulation permits the evaluation of all the elements of impedance and input motion matrices at a single step in terms of system matrices of boundary element method without solving any special problem, such as, unit displacement or load problem, as required by conventional methods. It further eliminates the complicated procedure and the need for using scattering analysis in the evaluation of input motion functions. The formulation is explained by considering a simple interaction problem involving an inclusion embedded in an infinite poroviscoelastic medium, which is under the influence of a dynamic excitation induced by seismic waves. In the formulation, an impedance relation is established for this interaction problem, suitable for performing the interaction analysis by substructure method, which permits carrying out the analysis for inclusion and its surrounding medium separately. The inclusion is first treated as poroviscoelastic, then viscoelastic and finally rigid, where the formulation in each of these cases is obtained consecutively as a special case of the previous one. It is remarkable to note that, a cavity problem where there is a hole in place of inclusion can be also considered within the framework of the present formulation. The formulation is assessed by applying it to some sample problems. The extension of the formulation to other types of interaction problems, such as, multi-inclusion problems, the analyses of foundations supported by a poroviscoelastic medium, etc., will be the subject of a separate study.Article Citation - WoS: 1A NEW FORMULATION FOR THE BOUNDARY ELEMENT ANALYSIS OF HEAT CONDUCTION PROBLEMS WITH NONLINEAR BOUNDARY CONDITIONS(Turkish Soc thermal Sciences Technology, 2019) Baranoglu, BesimAn effective numerical method based on the boundary element formulation is presented to solve heat conduction equations which are governed by the Fourier equation, with nonlinear boundary conditions on one or more sections of the prescribed boundary. The solution involves the manipulation of the system matrices of the boundary element method and obtaining a smaller ranked matrix equation in which the unknown is only the temperature difference over the nonlinear boundary condition region. This way, the iterations to deal with the nonlinear conditions are performed faster. After finding the solution over the nonlinear boundary condition region, the solution over the entire boundary is obtained as a post-process through a prescribed relation. An example with a proven exact solution is employed to assess the results.Article Citation - WoS: 22Citation - Scopus: 28Modeling of Dielectrophoretic Particle Motion: Point Particle Versus Finite-Sized Particle(Wiley, 2017) Cetin, Barbaros; Oner, S. Dogan; Baranoglu, BesimDielectrophoresis (DEP) is a very popular technique for microfluidic bio-particle manipulation. For the design of a DEP-based microfluidic device, simulation of the particle trajectory within the microchannel network is crucial. There are basically two approaches: (i) point-particle approach and (ii) finite-sized particle approach. In this study, many aspects of both approaches are discussed for the simulation of direct current DEP, alternating current DEP, and traveling-wave DEP applications. Point-particle approach is implemented using Lagrangian tracking method, and finite-sized particle is implemented using boundary element method. The comparison of the point-particle approach and finite-sized particle approach is presented for different DEP applications. Moreover, the effect of particle-particle interaction is explored by simulating the motion of closely packed multiple particles for the same applications, and anomalous-DEP, which is a result of particle-wall interaction at the close vicinity of electrode surface, is illustrated.Article An Adaptive Element Division Algorithm for Accurate Evaluation of Singular and Near Singular Integrals in 3d(Turkiye Klinikleri, 2021) Bayindir,H.; Baranoğlu,B.; Yazici,A.An adaptive algorithm for evaluation of singular and near singular integrals in 3D is presented. The algorithm is based on successive adaptive/selective subdivisions of the element until a prescribed error criteria is met. For evaluating the integrals in each subdivision, Gauss quadrature is applied. The method is computationally simple, memory efficient and can be applied for both triangular and quadrilateral elements, including the elements with nonplanar and/or curved surfaces. To assess the method, several examples are discussed. It has shown that the algorithm performs well for singular and near-singular integral examples presented in the paper and evaluates the integrals with very high accuracy. © TÜBİTAKDoctoral Thesis 3 Boyutlu Mikrokanallarda Parçacık Akış Problemleri ̇ıçin Sınır Eleman Yöntemi Tabanlı Özel Bir Paralel Formülasyon Tasarımı ve Uygulaması(2015) Karakaya, Ziya; Baranoğlu, Besim; Yazıcı, AliBu çalışmada mikroakışkan uygulamalarındaki kıvamlı yavaş akışta birden çok parçacığı izlemek için yeni bir formülasyon sunulmaktadır. Yöntem, sınır eleman matrislerinin manipülasyonu işlemininden sonra, parçacığın katı bünye hızları ile üzerine etki eden kuvvetleri ilişkilendiren bir denklem sistemi elde etmektedir. Formülasyon, SMP paralelleştirme yönteminin uygulandığı ardışık matris çarpımı işlemleri sonucunda özellikle parçacığın yörüngesinin takibi için tasarlanmıştır. Mevcut formülasyon, parçacık izleme işlemi için kullanılmak üzere etkili bir sayısal model sunmaktadır ve kolay bir şekilde birden çok fiziksel etkinin içerildiği çoklu-fizik simülasyonları için genişletilebilir olduğu görülmektedir.Doctoral Thesis Paralel, Genişletilebilir ve Genel Amaçlı Bir Sınır Eleman Yöntemi Uygulama Çerçevesinin Geliştirilmesi(2017) Bayındır, Hakan; Yazıcı, Ali; Baranoğlu, BesimBu çalışmada Sınır Eleman Yöntemi ile mühendislik problemlerini çözebilecek bir yazılım çerçevesi geliştirilmiştir. Bu çerçeve, problemlerin kolayca çözülmesini sağlayan, Akış adı verilen problem çözüm üniteleri ile yeni bir programlama modeli sunmaktadır. Ayrıca; yeteneklerin eklenmesi, özelliklerin probleme özel s ̧ekilde optimize edilmesi ve Akışların kolayca oluşturulabilmesi ile ilgili, çözüm adımları sağlayan fonksiyonlar ile yeni yaklaşımlar getirmektedir. Bu yazılım çerçevesi, yüksek performanslı ve paralel yazılım geliştirme süreçlerini kolaylaştırıcı özellikler içermektedir. Çerçeve, lineer elastik ve Laplace problemlerin çözülmesi ile ilgili Akışların program- lanması ile test edilmiş, çerçeve, problemleri paralel algoritmalar kullanarak dog ̆ru s ̧ekilde ve az bir programlama uğraşı ile çözerek hedeflerine ulaşmıştır.
