This paper presents the capability of the Computational Fluid Dynamics (CFD) Fluent V15.0 software to predict the transverse single phase flow across a rod bundle using Large Eddy Simulation (LES). To meet this objective, an advanced comparison with non-intrusive velocity measurements (Laser Doppler Velocimetry /LDV/, Particle Image Velocimetry based on cross-correlation /PIV/ and based on Optical Flow /OF/) is carried out. Beyond the classical comparison of time-averaged (mean) and standard deviation velocity profiles (spatial information), the turbulent flow is analyzed via local Power Spectral Densities /PSD/ and Proper Orthogonal Decomposition /POD/ comparison. Generally applied to academic cases (e.g. flow past a cylinder at Re = 100), POD is conducted in this paper on both CFD and PIV turbulent velocity fields around a rod inside a rod bundle. Through the spectral and fluctuating energy content of a turbulent flow, the Fluent LES turbulent model is further validated on a complex industrial test case (rod bundle mock-up of a water pressurized steam generator).