Lift forces acting on particles play a central role in many cases, such as sediment transport, proppant transport in fractured reservoirs, removal of drill cuttings in horizontal drill holes and cleaning of particles from surfaces. We study the problem of lift using 2D direct numerical simulations and experimental data. The lift-off of single particles and many particles in horizontal flows follow laws of similarity, power laws, which may be obtained by plotting simulation data on log-log plots. Data from slot experiments for fractured reservoirs is processed (for the first time) on log-log plots. Power laws with a parameter dependent power emerge as in the case of Richardson-Zaki correlations for bed expansion by drag. (C) 2002 Published by Elsevier Science Ltd.