XFlow is a particle-based Lattice Boltzmann technology solver for high fidelity Computational Fluid Dynamics (CFD) applications as a part of SIMULIA’s Fluids Simulation portfolio. XFlow offers multiphase and moving parts modeling capabilities specially focused on lubrication workflows such as gearboxes and electric motor drives.

Regardless of the system complexity, gear types or lubrication method, XFlow provides detailed insight into the system performance. Lubrication simulation can reduce the number of physical tests, and it provides quantitative predictions for results like wetted area and churning losses that can be very difficult or impossible to measure experimentally.

XFlow’s automatic lattice generation minimizes user inputs thereby reducing time and effort in the meshing and pre-processing phase. XFlow fully supports GPU computing to accelerate the time to solution.  Problem setup and results exploration are easy and intuitive, enabling users to focus their efforts on design iteration and optimization. In addition, advanced rendering capabilities provide realistic visualization to gain deeper insight into flow performance.

The state-of-the-art technology of XFlow for lubrication enables users to address other related CFD workflows involving high frequency transient simulations with real moving geometries, complex multiphase flows and free surface flows.

Beyond Lattice Boltzmann

In non-equilibrium statistical mechanics, the Boltzmann equation describes the behavior of a gas modeled at mesoscopic scale. As opposed to standard Multiple Relaxation Time (MRT), the scattering operator in XFlow is implemented in central moment space, naturally improving the Galilean invariance, the accuracy and the stability of the code. 

Particle-based kinetic solver

XFlow features a novel particle-based kinetic algorithm that has been specifically designed to perform very fast with accessible hardware. The discretization approach in XFlow avoids the classic domain meshing process and the surface complexity is not a limiting factor anymore. The user can easily control the level of detail of the underlying lattice with a small set of parameters, the lattice is tolerant to the quality of the input geometry, and adapts to the presence of moving parts.

Turbulence modeling: High fidelity WMLES

XFlow features the highest fidelity Wall-Modeled Large Eddy Simulation (WMLES) approach to the turbulence modeling.

The underlying state-of-the-art LES, based on the Wall-Adapting Local Eddy (WALE) viscosity model, provides a consistent local eddy-viscosity and near wall behavior. It also performs in CPU-times similar to most codes providing just RANS analysis. XFlow uses a unified non-equilibrium wall function to model the boundary layer. This wall model works in most cases, meaning that the user do not have to select between different models and take care of the limitations related to each scheme.