Measures of particle disorder

In the present work we describe a numerical algorithm which gives a qualitative measure of the disorder in the particle distribution in two dimensions. The proposed measure of the particle disorder has been tested on specific configurations obtained through perturbation of a regular lattice. It turned out that the disorder measure may be qualitatively related to the mean absolute value of the perturbation. Finally, the proposed algorithm has been applied to dynamical test cases characterized by different flow features and by the use of different SPH variants.