## Abstract / Description of output

GISS is a powerful and efficient 3D Direct Numerical Simulation (DNS) solver to simulate solid-fluid flows with immersed solids in unprecedented detail.

The GISS numerical solver comprises two sub-solvers: i) The Gerris flow solver and ii) the Immersed Solid Solver. A two-step solution strategy is used. First, the 3D flow equations around the body are solved using the Gerris Engine (developed by Stéphane Popinet) to obtain velocity and pressure fields. These are then used to calculate the hydrodynamic force field on the surface of the immersed solid. Second, the calculated forces are passed on to the solid solver which calculates the new position of the immersed body using rigid body equations for translation and rotation. These steps allow for two-way solid-fluid coupling at every time step. The solver allows for arbitrary number of solids with arbitrary geometric features in six degree of freedom (6DOF)} motion. The solver can perform dynamical quad/octree mesh optimisation in a Cartesian framework, which greatly simplifies the procedure for mesh generation.

The GISS numerical solver comprises two sub-solvers: i) The Gerris flow solver and ii) the Immersed Solid Solver. A two-step solution strategy is used. First, the 3D flow equations around the body are solved using the Gerris Engine (developed by Stéphane Popinet) to obtain velocity and pressure fields. These are then used to calculate the hydrodynamic force field on the surface of the immersed solid. Second, the calculated forces are passed on to the solid solver which calculates the new position of the immersed body using rigid body equations for translation and rotation. These steps allow for two-way solid-fluid coupling at every time step. The solver allows for arbitrary number of solids with arbitrary geometric features in six degree of freedom (6DOF)} motion. The solver can perform dynamical quad/octree mesh optimisation in a Cartesian framework, which greatly simplifies the procedure for mesh generation.

Original language | English |
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Type | Gerris Immersed Solid Solver (GISS) |

Media of output | Open-Source 3D Direct Numerical Simulation (DNS) solver |

Publication status | Published - Nov 2020 |

## Keywords / Materials (for Non-textual outputs)

- DNS solver
- Open Dynamics Engine
- solid modelling
- immersed boundary method
- complex solid geometries