A three-dimensional unsteady-state Eulerian multi-fluid CFD model was developed to simulate the hydrodynamic behavior of inclined gas-liquid cocurrent downflow packed beds under ON-OFF liquid, ON-OFF gas, and gas/liquid alternating cyclic operations. Validation of the CFD simulation results was performed with experimental data provided by electrical capacitance tomography imaging. Incorporation in the Eulerian multifluid CFD model of capillary pressure and mechanical dispersion force was essential to accurately capture the transient spatial heterogeneities arising in tilted packed beds under different cyclic modulation strategies. The applied CFD model was able to satisfactorily predict the values of liquid holdup and pressure drop as well as the morphological characteristics of the traveling waves inside the bed for the examined flow modulations. (C) 2017 American Institute of Chemical Engineers