Scaling properties of collective effects at RHIC

Azimuthal anisotropy is one of the key observables to study the properties of matter created in high energy heavy-ion collisions at RHIC and the LHC. The collective behaviour is quantified in terms of anisotropy coefficients v_n measured with respect to their corresponding event planes. Predictions from the viscous hydrodynamics for the scaling of the anisotropic flow coefficients v_n with eccentricity, system size and transverse energy are tested using the recent data from PHENIX Collaboration. (paper)