For investigation of natural phenomenon, numerical simulation has attracted considerable attention from many sciences in the engineering field. In this paper, the parameters of hydrodynamics around cylindrical structures in steady current (specially, vortex-shedding frequency which results oscillating lift force and also Reynolds number) have been described then flow regime around specified piles and its characteristics have been investigated by analysis of experimental data and power spectral density (in frequency domain) of the time series of the recorded lift forces which exerted on the piles. Then, the experimental condition of the supposed data, have been modeled numerically by CFD methods and fluent package. Output results which have been obtain form software compared with foregoing experimental data and simulating proceed have been validated. Furthermore, position of the separation point (as a function of Re), has been estimated by output of the fluent.