Chrono::FSI is a module for modeling and simulation of fluid-solid interaction problem. It provides the framework for coupling a Chrono multibody system (for rigid and/or flexible dynamics) with an arbitrary FSI-aware fluid solver. Two related Chrono submodules are available:

Chrono::FSI-SPH which implements a fluid solver based on the Smoothed Particle Hydrodynamics method
Chrono::FSI-TDPF which implements a fluid solver based on the Time Domain Potential Flow method

Features

The FSI-SPH module allows users to:

Use the module as a CFD solver for fluid mechanics problems via the following Lagrangian methods:
- Implicit incompressible SPH (ISPH)
- Explicit weakly compressible SPH (WCSPH)
Use the module as a solver for granular material dynamics (CRM) via the following Lagrangian method:
- Explicit weakly compressible SPH (WCSPH)
Use the module for solving fluid-solid interaction problems that feature:
- Rigid bodies
- Flexible bodies (FEA models)
Use the module for solving rigid multi-body dynamics and its interaction with CRM deformable terrain
- Rover/vehicle mobility simulation on granular material terrain

The FSI-TDPF module allows users to:

Use the module for solving fluid-solid interaction problems that feature rigid multibody systems

Requirements

To build the FSI-SPH module and related applications, a CUDA installation and appropriate compiler are required.
The FSI-SPH module requires CUDA version 12.9 (NOTE: CUDA 13 is not yet supported).
To build the FSI-TDPF module and related applications, HDF5 support is required and must be enabled (CH_ENABLE_HDF5).
To run applications based on the FSI-SPH module an NVIDIA GPU card is required.

Building instructions

Repeat the instructions for the full installation.
Set CH_ENABLE_MODULE_FSI to 'on'.
If all dependencies are satisfied, both the FSI-SPH and FSI-TDPF modules are enabled. Optionally disable the FSI-SPH module (via CH_ENABLE_MODULE_FSI_SPH) or the FSI-TDPF module (via CH_ENABLE_MODULE_FSI_TDPF)
If the FSI-SPH module is enabled, optionally set CH_USE_SPH_DOUBLE to ON to use double precision in the SPH solver.
The single precision FSI solver has been tested to have similar level of accuracy as the double precision solver with close to a 2X performance improvement.
Press 'Configure' again, then 'Generate', and proceed as usual in the installation instructions.

How to use it

Look at the API section of the Chrono::FSI module for documentation about the base classes and functions.
Look at the API section for documentation of the classes and functions for the FSI-SPH solver.
Look at the API section for documentation of the classes and functions for the FSI-TDPF solver.
Look at the C++ source of demos to learn how to use the functions of these modules.

MacOS support

This module cannot be built for MacOS, Nvidia GPU hardware and CUDA are unsupported.