A Study of Unsteady Rotor–Stator Interactions

Abstract

This work is concerned with simulations of rotor-generated unsteady response of the turbulent flow in a stator. The rotor’s effect is represented by moving cylinders of equivalent drag coefficient that produce passing wakes at the entrance of the stator. The unsteady incompressible Navier–Stokes equations are solved on a staggered grid and eddy viscosities are obtained using a k –ε model. The rotor-generated wakes were found to produce a pressure field at the stator’s entrance that increases in the direction of the wake traverse. At a streamwise distance equal to the distance between the stator blades, the pressure becomes uniform across the channel and the oscillations in the pressure field decay. Because of the initial asymmetry of the pressure field, the time-averaged mean velocity is no longer symmetric. This asymmetry of the mean flow continues along the passage even after the pressure has regained its symmetry. As a result of the passing of the rotor-generated wakes, large periodic oscillations are introduced into the mean velocity and turbulence energy. The time-averaged turbulence energy and the wall shear stress increases in the direction of the rotor traverse.