Discrete Element Method (DEM) is a numerical method that evaluates the interaction between particles and particle-boundaries [1]. The accuracy of the DEM simulations depends on several interaction parameters such as sliding friction and rolling friction coefficients. Most recent studies have shown that a draw down test can provide four criteria: angle of repose, shear angle, mass in the upper/lower box after test is done and mass flow rate that were used to calibrate bulk material sliding friction and rolling friction coefficients [2-3]. In general, these studies have used a fix aperture size of the upper box leading to a specific behaviour flow regime. In this study, three different flow regimes have been studied to evaluate if one set of unique parameters can reproduce the same response for these scenarios. A draw down test was carried out using gravel with particle size between 8-12.5 mm. The aperture size used were 50, 100 and 150 mm. During the test, the transient load was measured using a load cell in the upper box and pictures were taken after the test was done. DEM simulations were performed using the EDEM software where a single spherical and multi-sphere particle shape were used to obtain draw down calibration parameters by varying sliding friction and rolling friction parameters between 0.1 to 0.8 with an step of 0.1. When overlapping the four bulk criteria from 100 and 150 mm in aperture size using single sphere, it was possible to obtain a unique set of parameters. However, for 50 mm there was no overlapping which may indicate that using single sphere might not be accurate for all flow regimes. When using multi-sphere particle, the overlap led to a wide range of sliding friction coefficient for all cases, and although when overlapping the three scenarios there was no feasible region, it shows a tendency where a unique set of parameters might provide an approximate solution for all cases.