Hybridizable discontinuous Galerkin method for nonlinear hyperbolic integro-differential equations

In this paper, we present the hybridizable discontinuous Galerkin (HDG) method for a nonlinear hyperbolic integro-differential equation. We discuss the semi-discrete and fully-discrete error analysis of the method. For the semi-discrete error analysis, an extended type mixed Ritz-Volterra projection is introduced for the model problem. It helps to achieve the optimal order of convergence for the unknown scalar variable and its gradient. Further, a local post-processing is performed, which helps to achieve super-convergence. Subsequently, by employing the central difference scheme in the temporal direction and applying the mid-point rule for discretizing the integral term, a fully discrete scheme is formulated, accompanied by its corresponding error estimates. Ultimately, through the examination of numerical examples within two-dimensional domains, computational findings are acquired, thus validating the results of our study.