scholarly journals Some new results for geometric inverse problems with the method of fundamental solutions

Author(s):  
P. P. Carvalho ◽  
A. Doubova ◽  
E. Fernández-Cara ◽  
J. Rocha de Faria
2020 ◽  
Vol 37 (9) ◽  
pp. 3293-3319
Author(s):  
Adam Basílio ◽  
Fran Sérgio Lobato ◽  
Fábio de Oliveira Arouca

Purpose The study of heat transfer mechanisms is an area of great interest because of various applications that can be developed. Mathematically, these phenomena are usually represented by partial differential equations associated with initial and boundary conditions. In general, the resolution of these problems requires using numerical techniques through discretization of boundary and internal points of the domain considered, implying a high computational cost. As an alternative to reducing computational costs, various approaches based on meshless (or meshfree) methods have been evaluated in the literature. In this contribution, the purpose of this paper is to formulate and solve direct and inverse problems applied to Laplace’s equation (steady state and bi-dimensional) considering different geometries and regularization techniques. For this purpose, the method of fundamental solutions is associated to Tikhonov regularization or the singular value decomposition method for solving the direct problem and the differential Evolution algorithm is considered as an optimization tool for solving the inverse problem. From the obtained results, it was observed that using a regularization technique is very important for obtaining a reliable solution. Concerning the inverse problem, it was concluded that the results obtained by the proposed methodology were considered satisfactory, as even with different levels of noise, good estimates for design variables in proposed inverse problems were obtained. Design/methodology/approach In this contribution, the method of fundamental solution is used to solve inverse problems considering the Laplace equation. Findings In general, the proposed methodology was able to solve inverse problems considering different geometries. Originality/value The association between the differential evolution algorithm and the method of fundamental solutions is the major contribution.


Author(s):  
I Pérez-Arjona ◽  
L Godinho ◽  
V Espinosa

Abstract The method of fundamental solutions has been applied to evaluate the influence of fish models geometrical features on the target strength (TS) directivity and TS frequency response of swimbladdered fish. Simplified models were considered for two fish species: gilt-head sea bream (Sparus aurata, Linnaeus 1758) and Atlantic salmon (Salmo salar, Linnaeus 1758), and different geometrical details of their morphology were studied, such as backbone presence, and its curvature or the inclusion of vertebrae modulation. Swimbladder shape and tilt, together with the inclusion of backbone (and its realistic curvature) for dorsal measurements were the most important features for proper estimation of mean TS. The estimation of mean TS is considered including the effect of fish tilt, the echosounder frequency, and the fish-to-transducer distance.


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