The effects of grid size and subgrid length-scale are investigated using Delayed-Detached Eddy Simulation(DDES) based on Spalart-Allmaras(S-A) turbulence model and k-w Shear Stress Transport(SST) turbulence model. Driver & Seegmiller"s experimental results are used to validate the numerical results. Various grid densities and subgrid length-scale definitions are tested to investigate the effect on the numerical results. The results of the simulations shows that the volume method for subgrid length-scale is more resistant to periodic direction grid size than the maximum method: Using appropriate grid density and subgrid length-scale, both S-A based DDES and SST based DDES methods show in general good correlation with the experimental data.