Effect of turbulence model on unsteady fluid flow simulation in radial fan

In case of unsteady fluid flow in radial fan, an effect of turbulence model on unsteady flow simulation results is investigated. As the fan flow is wall bounded and dominated by separation, an emphasis is put on comparison of realizable k-epsilon unsteady RANS and Spalart-Allmaras DES turbulence models. The calculation of flow instabilities for two different types of the shroud and two different number of blades are performed. The results are transferred, via FFT analysis, in frequency domain which is relevant in unsteady phenomena analysis.