Numerical simulation of unsteady vortex in the wake of cascade flow

Vortex usually exists in cascade passage due to complex unsteady viscous flow; It requires the high efficiency numerical method to capture the generation and shedding of vortex. A high resolution non-oscillatory scheme and LU-SGS implicit algorithm with Baldwin-Lomax algebraic turbulence model are employed to solve two dimensional Navier-Stokes equations. The numerical study of unsteady vortex in two dimensional cascades is provided. Vortex separation and shedding with different inlet Mach numbers are captured through the analysis of instantaneous entropy and pressure contours, which can reasonably indicate the mechanics of turbulence flow. The calculations show that the method plays an important role in numerical simulations of unsteady viscous flow; the generation, development and disappearance of vortex are described clearly by numerical simulation; our method of simulation can be used for investigating the effect upon isolated rotor and multi-row blade with tip clearances.