# V. Flow by VORCAT – how to simulate turbulence mesh free…

The software is one of the most sophisticated vortex method commercial software I came across during my thesis.

Peter Bernard’s (and partners) Vorcat is based upon Alexandre Chorin publications of some fascinating ideas concerning numerical modelling with mesh free methods.

Chorin proposed a discretization of the vorticity equation by vortex entities, linking them to the velocity field by Bio-Savart (linking not inducing… 😉 ) and handling each of the terms in the transport equations from a purely mathematical stand point to achieve a semi-lagrangian method. The advection-diffusion of vortex entities is achieved by advection of random walking (e.g. “Random Walk” concept) vortex entities, turbulent energy cascade to high wavenumbers is evident by stretching of these vortex entities and the fractal intermittent nature of turbulence by folding of the entities (a consequence of the law of conservation of energy).

This of course in a nutshell…

Vorcat’s team have taken a huge step forward in setting up highly sophisticated algorithms to extend Chorin’s ideas along with impressive graphics to CFD.

The advection-diffusion of large vortex entities, the cascade of energy through stretching and fractalization until a threshold is met that a folded entity is small enough to be taken out of the picture – removal of hairpins (and by all means subgrid filtering… familiar?).

The code has actually been validated to some well known benchmarks (for isotropic turbulence it could be actually considered an LES).

Vorcat – research and publications