An Arbitrarily High-Order Fully Well-balanced Hybrid Finite Element-Finite Volume Method for a One-dimensional Blood Flow Model

In this paper, we propose an arbitrarily high-order accurate fully well-balanced numerical method for the one-dimensional blood flow model. The developed method is based on a continuous representation of the solution and a natural combination of the conservative and primitive formulations of the studied PDEs. The degrees of freedom are defined as point values at cell interfaces and moments of the conservative variables inside the cell, drawing inspiration from the discontinuous Galerkin method. The well-balanced property, in the sense of an exact preservation of both the zero and non-zero velocity equilibria, is achieved by a well-balanced approximation of the source term in the conservative formulation and a well-balanced residual computation in the primitive formulation. To lowest (3rd) order this method reduces to the method developed in [Abgrall and Liu, A New Approach for Designing Well-Balanced Schemes for the Shallow Water Equations: A Combination of Conservative and Primitive Formulations, arXiv preprint, arXiv:2304.07809]. Several numerical tests are shown to prove its well-balanced and high-order accuracy properties.