A GPU-accelerated numerical model for nearshore scalar transport by dispersive shallow water flows

A GPU-accelerated nearshore scalar transport model with the Boussinesq-type wave solver is introduced. The depth-integrated advection-diffusion equation is implemented into Celeris Advent, the firstly-developed open-source Boussinesq wave model equipped with an interactive system supporting simultaneous visualization and data exchange between a user and the computing unit. A hybrid finite volume-finite difference scheme is adopted to discretize the governing equations, and the modified HLL Riemann solver for satisfying the conservation property of the scalar concentration is applied for an accurate approximation of scalar numerical flux. A source-function wavemaker in conjunction with alongshore periodic boundary conditions and a wave-breaking model are implemented to more precisely replicate the nearshore hydrodynamic processes. Several numerical tests using analytical solutions and experimental data are performed to validate the model. Finally, field-scale dye release experiments are reproduced numerically, assessing the applicability of the proposed model in predicting nearshore scalar transport by dispersive hydrodynamics. The proposed model is expected to serve as an advanced tool for real-time assessment and mitigation of marine pollution incidents.