A hybrid solver based on efficient BEM-potential and LBM-NS models: Recent BEM developments and applications to naval hydrodynamics
Date of Original Version
We report on recent developments of a 3D hybrid model for naval hydrodynamics based on a perturbation method, in which velocity and pressure are decomposed as the sum of an inviscid flow and a viscous perturbation. The far-to near-field inviscid flows are solved with a Boundary Element Method (BEM), based on fully nonlinear potential flow theory, accelerated with a fast multipole method (FMM), and the near-field perturbation flow is solved with a Navier-Stokes (NS) model based on a Lattice Boltzmann Method (LBM) with a LES modeling of turbulent properties. The BEM model is efficiently parallelized on CPU clusters and the LBM model on massively parallel GPGPU co-processors. The hybrid model formulation and its latest developments and implementation, in particular, regarding the improvement and validation of the model for naval hydrodynamics applications, are presented in a companion paper by O'Reilly et. al (2017), in this conference. In this paper, we concentrate on the BEM model aspects and show that the BEM-FMM can accurately solve a variety of problems while providing a nearly linear scaling with the number of unknowns (up to millions of nodes) and a speed-up with the number of processors of 35-50%, for small (e.g., 24 cores) to large (e.g., hundreds of cores) CPU clusters.
Proceedings of the International Offshore and Polar Engineering Conference
Mivehchi, Amin, Jeffrey C. Harris, Stéphan T. Grilli, Jason M. Dahl, Chris M. O'Reilly, Konstantin Kuznetsov, and Christian F. Janssen. "A hybrid solver based on efficient BEM-potential and LBM-NS models: Recent BEM developments and applications to naval hydrodynamics." Proceedings of the International Offshore and Polar Engineering Conference , (2017): 721-728. https://digitalcommons.uri.edu/oce_facpubs/42