This paper describes numerical simulation and matching experimental results for oscillatory flow within a baffled tube containing tri-orifice baffles. The numerical simulation implemented a non-standard approach based on Implicit Large Eddy Simulation (ILES) to predict the flow in a situation where complex eddy formation occurs due to periodic separation for each oscillation of the flow. The set of performed experiments showed that within the cavity between each baffle, the flow structure was complex with elements of periodicity and a wide range of length scales. Conventional Large Eddy Simulation and comparison with experiments were used to validate the ILES results. It was concluded that the gross flow structure was captured by ILES, indicating that the numerical scheme is suitable for computation in the complex flow situation. In addition, ILES methodology was used to study the effect of increasing the oscillation frequency on the radial and axial velocities. (C) 2012 Elsevier Ltd. All rights reserved.