 Open Access

ARTICLE

# Solving the Inverse Problems of Laplace Equation to Determine the Robin Coefficient/Cracks' Position Inside a Disk

Chein-Shan Liu1
Department of Civil Engineering, National Taiwan University, Taipei, Taiwan. E-mail: liuchei.nshan@msa.hinet.net

Computer Modeling in Engineering & Sciences 2009, 40(1), 1-28. https://doi.org/10.3970/cmes.2009.040.001

### Abstract

We consider an inverse problem of Laplace equation by recoverning boundary value on the inner circle of a two-dimensional annulus from the overdetermined data on the outer circle. The numerical results can be used to determine the Robin coefficient or crack's position inside a disk from the measurements of Cauchy data on the outer boundary. The Fourier series is used to formulate the first kind Fredholm integral equation for the unknown data f(θ) on the inner circle. Then we consider a Lavrentiev regularization, by adding an extra term αf(θ) to obtain the second kind Fredholm integral equation. The termwise separable property of kernel function allows us to obtain a closed-form regularized solution, of which the uniform convergence and error estimation are proved. Then we apply this method to the inverse Cauchy problem, the unknown shape of zero-potential problem, the problem of detecting crack position, as well as the problem of unknown Robin coefficient. These numerical examples show the effectiveness of the new method in providing excellent estimates of the unknown data.

### Keywords

Laplace equation, Inverse Cauchy problem, Fredholm integral equation, Lavrentiev regularization, Robin coefficient, Crack position

Liu, C. (2009). Solving the Inverse Problems of Laplace Equation to Determine the Robin Coefficient/Cracks' Position Inside a Disk. CMES-Computer Modeling in Engineering & Sciences, 40(1), 1–28. This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

View

• ### 0

Like

Related articles
• Chein-Shan Liu   