During this decade, the interest in the aerodynamics around a steady rectangular cylinder has grown up so vastly that various researchers and scientist working on bluff body aerodynamics contributed to the Benchmark on the Aerodynamics of a 5:1 cylinder (BARC) launched in 2008. These contributions are experimental or numerical using various simulation approaches like URANS, LES, VMS, hybrid URANS-LES, VMS-LES etc. This work is a numerical contribution based on Large-eddy simulations (LES) carried out using a spectral element open-source code,NEK5000. The flow Reynolds number is kept high (40000) so that the presence of turbulence could be observed in the stationary sharp-edged rectangular cylinder. It is attempted to use the dynamic Smagorinsky model and the single filtering model to close the LES equations. One of the examples given by NEK producers called turbChannel is verified and used to have the desired code to run the simulation. Both 2D and 3D simulations are done and the obtained results like bulk parameters, mean value and RMS of the pressure coefficient along the cylinder surface and streamlines of the mean velocity field are tried to compare with the result obtained by Ribeiro for the 2D case and Bruno et al. for the 3D case.