Varun Gupta, Peter G. Harrison
We obtain the Laplace transform of the fluid level probability density function, in terms of the on-period density function, for a fluid queue (or reservoir) with on-off input at equilibrium. We further obtain explicit expressions for the moments of fluid level in terms of the moments of the on-period and hence derive an algorithm for the moments of fluid level at every queue in a tandem network. It turns out that to calculate the kth moment at the ith queue, only the first k+1 moments of the on-period of the input process to the first queue are required.
Information from pubs.doc.ic.ac.uk/fluid-varun.