The lattice Boltzmann model has evolved from the lattice gas model. There are a number of difficulties with the lattice gas approach to fluid modelling; various modifications have been made to overcome these difficulties and the outcome is the lattice Boltzmann model. As the name suggests this technique involves simulating the Boltzmann equation
where 
is a `collision' function,
is the body force per unit mass,
is the particle velocity and
is the distribution function.
The distribution function is a statistical parameter
from which the macroscopic properties of the fluid can be found.
The simulation of the Boltzmann equation is performed on a regular lattice
and the forms of the collision function 
is taken to be the
BGK [6] collision operator which was fist considered to represent
collisions in the non-discrete Boltzmann equation.
The computation reflects the evolution from the lattice gas model. The
model is updated in the same manner as the lattice gas model except that
now, instead of considering individual particles to be travelling along
the links, it is the distribution function which is evolved.
The lattice Boltzmann model has the advantages associated with the
lattice gas model but all the lattice gas difficulties have been overcome. Thus
the lattice Boltzmann model is an ideal tool in fluid simulation.