In most industrial application, fluid flow is turbulent and in the other word, flow velocity magnitude and direction fluctuate during the time. There are three models for investigating turbulence effects. Direct numerical simulation (DNS) in DNS no modeling required. DNS solving is not practical for simulating industrial work that Reynolds number is very high. The computational cost of DNS is related to cube of Reynolds number. The computational cost of this model is very high and is not proposed for industrial work. Needs high number of element and consequence high-performance CPU (HPC) and RAM.in application that detail of fluid flow and eddies is important we must use DNS. Another method is Reynolds Average Naiver Stokes (RANS). By using this method we just find effect of turbulence and eddies, in the other word we will find the Reynolds stress magnitude and turbulence viscous. The computational cost of this model is lower than DNS and can be simulated in steady state. There is another model that can be solved in some industrial work that we should know more about eddies and vortexes. This model is used for finding large eddies behavior. We know that most of passive scalar and mass and momentum are transferred by large eddies. Large eddies behavior is more related to special problem and geometry and boundary condition related to especial work but small eddies behavior is more universal. So we can simulate small eddies by various models such as RANS model (k-epsilon, k-omega and so on).