Bhatnagar–Gross–Krook operator


The Bhatnagar–Gross–Krook operator term refers to a collision operator used in the Boltzmann Equation and in the Lattice Boltzmann method, a Computational fluid dynamics technique. It is given by the following formula:
where is a local equilibrium value for the population of particles in the direction of link The term is a relaxation time, and related to the viscosity.
The operator is named after Prabhu L. Bhatnagar, Eugene P. Gross, and Max Krook, the three scientists who introduced it in a paper in Physical Review in 1954.