A. Marcano - C.V.G. EDELCA Dept. of Hydraulics, San Felix, Estado Bolívar, Venezuela
L. Rojas-Solórzano - Associate Professor, Dept. of Energy Conversion, Universidad Simón Bolívar, Venezuela
M. Reyes - Associate Professor, Dept. of Thermodynamics, Universidad Simón Bolívar, Venezuela
J. Marín - Graduate Student, Dept. of Mechanical Engineering, Universidad Simón Bolívar, Venezuela

In this paper, the 3-D CFD simulation of the free-surface flow approaching the intakes of Caruachi Powerhouse is presented. The aim of the investigation is to determine whether or not vortex structures are likely to appear from the water surface through the intakes, as the result of the presence of cofferdams placed few meters upstream of the intakes. The presence of cofferdams was a note of concern with regard to the effects they might have on the turbine intakes once the hydroelectric central starts operating. In all the considered conditions, results did not show neither strong surface vortices in the proximities of the Powerhouse intakes, nor air entrainmententrapment towards the intakes, which reflects the safe operation of the turbines in the presence of the cofferdams. The latter added in decision taking on leaving the cofferdams submerged instead of removing them, which resulted in cost savings for the project.