## Abstract

Motivated by the problem of developing accurate and stable time-stepping methods for the single-layer potential equation for acoustic scattering from a surface, we present new convergence results for piecewise polynomial discontinuous Galerkin (DG) approximations of a first-kind Volterra integral equation of convolution kernel type, where the kernel K is smooth and satisfies K(0) ? 0. We show that an mth degree DG approximation exhibits global convergence of order m when m is odd and order m+1 when m is even. There is local superconvergence of one order higher (i.e. order m+1 when m is odd and m+2 when m is even), but in the even order case, there is superconvergence only if the exact solution u of the equation satisfies u^{(m+1)}(0)=0. We also present numerical test results which show that these theoretical convergence rates are optimal.

Original language | English |
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Pages (from-to) | 856-881 |

Number of pages | 26 |

Journal | IMA Journal of Numerical Analysis |

Volume | 29 |

Issue number | 4 |

DOIs | |

Publication status | Published - Oct 2009 |

## Keywords

- Discontinuous Galerkin approximations
- Global convergence
- Local superconvergence
- Volterra integral equations of the first kind