M. J. Ketabdari - Associate Professor, Faculty of Marine Technology, Amirkabir University of Technology
H Saghi - PhD student of Hydraulics, Department of Civil Engineering, Ferdowsi University
H Rezaei - PhD student of Hydrodynamic, Faculty of Marine Technology, Amirkabir University of Technology

For fluid flow the governing equations can be solved using numerical methods. Bases of these equations are Momentum and Continuity leading to Navier-Stokes equations. There are several methods such as Simple, PISO and Fractional Step for solving these equations. In solution procedure, it needs to decide where to store the velocity components. To evaluate this, staggered and collocated grids can be used. On staggered grid, the velocity components are stored at the cell face and the scalar variables such as pressure are stored at the central nodes. However on collocated grids, all parameters are defined at the same location at the central nodes. The advantage of staggered grids is more accurate pressure gradient estimation. In collocated grids method, solving the equations is simpler as all parameters can be stored at the same location. In this paper a comparison between collocated and staggered grids for solving Navier-Stokes equations is presented. The results were validated using standard tests such as led driven cavity,channel and backward facing step. Discussion is made on accuracy of these methods to estimate horizontal and vertical velocity profiles.

Navier-Stokes Equations, Staggered grid, Collocated grid, Backward facing step, PISO