## Abstract

We consider the conductivity problem in the presence of adjacent circular inclusions with constant conductivities. When two inclusions get closer and their conductivities degenerate to zero or infinity, the gradient of the solution can be arbitrary large. In this paper we derive an asymptotic formula of the solution, which characterizes the gradient blow-up of the solution in terms of conductivities of inclusions as well as the distance between inclusions. The asymptotic formula is expressed in bipolar coordinates in terms of the Lerch transcendent function, and it is valid for inclusions with arbitrary constant conductivities. We illustrate our results with numerical calculations.

Original language | English |
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Pages (from-to) | 131-156 |

Number of pages | 26 |

Journal | Journal of Mathematical Analysis and Applications |

Volume | 421 |

Issue number | 1 |

DOIs | |

Publication status | Published - 2015 Jan 1 |

Externally published | Yes |

## Keywords

- Anti-plane elasticity
- Bipolar coordinates
- Conductivity equation
- Gradient blow-up
- Lerch transcendent function

## ASJC Scopus subject areas

- Analysis
- Applied Mathematics