Measurement of the first and second moments of the velocity distribution in two-dimensional vibro-fluidised granular beds

Previously developed methods of determining granular temperature have been successful at estimating granular temperature only when the mean convective velocity is small. To avoid this problem, we examine methods of extracting both the granular temperature and the convection velocity using the mean squared displacement. Unfortunately, equations describing Brownian motion were found to be unstable when large convection currents were present, due to the non-linear regression techniques employed. However, a two-stage process that looks at both the long and short time mean squared displacement behaviour was found to be significantly more robust over a greater range of convection velocities.