Abstract: A large eddy simulation(LES)approach based on the weakly compressible hydrodynamic equation for the relative motion is developed in a rotational coordinate system,and employed in simulating 3-D flow through a francis turbine runner.The finite volume approach with predictor corrector method and a law of the wall for the solid wall condition are used.The velocity and pressure fields are obtained and compared with the computated results by the k-ε model,showing that the 3-D LES approach can give realistic results of the flow field.