Three-Dimensional Time-Resolved Inlet Guide Vane-Rotor Potential Field Interaction

To investigate and quantify the three-dimensional time-varying characteristics of inlet guide vane (IGV) wakes, including the effect of the potential field of a downstream rotor, a series of experiments are performed in a high-speed fan stage. The unsteady three-dimensional velocity and total pressure fields downstream of the IGVs and upstream of the rotor have been measured across one vane passage and time resolved over several rotor blade passage periods. These unique data will be compared with several wake correlations and analyzed to determine the time-varying characteristics of the IGV wakes. Earlier two-component velocity measurements identified a unique interaction occurring between the rotor potential field and the IGV wakes. The rotor potential field increases as the IGV wakes approach the rotor, resulting in a constructive/destructive interaction. Measurements of the IGV wake at times of maximum and minimum interaction show that the constructive interaction increases the velocity deficit and semiwake width as the distance from the rotor decreases. A two-dimensional vortical-potential gust splitting analysis will be implemented to determine the vortical and potential harmonic wake gust forcing functions upstream of the rotor over one rotor blade passing period.