Characterization of the Response of a Single Rotor in Hover to Dynamic Collective Pitch
Publication Date
1-1-2023
Document Type
Conference Proceeding
Publication Title
FORUM 2023 - Vertical Flight Society 79th Annual Forum and Technology Display
Abstract
The flow fields of a 2m-diameter two-bladed single rotor were measured using particle image velocimetry, and computed using a coupled RCAS-VVPM analysis. Dynamic collective pitch inputs were introduced in terms of stepped sines with an amplitude of 1◦, and frequencies of 0.0/rev, 0.2/rev, 0.3/rev, 0.4/rev, 0.6/rev, and 0.7/rev. Phase-resolved particle image velocimetry measurements were performed to capture the flow field response to the dynamic pitch inputs at an azimuthal location of ψb = 90◦. Flow field information was acquired at specific measurement locations in order to capture the dynamic effects at the azimuthal plane of interest. A total of ten measurement locations were captured for each excitation frequency. At each measurement location 200 instantaneous flow realizations were captured. The goal of this study was to develop an experimental and numerical procedure to investigate the wake and loads of a single isolated rotor in hover in response to stepped sine pitch inputs at a nominal collective pitch angle of θ0 = 8◦ and nominal blade loading of CT/σ = 0.08. The change in rotor thrust ranged from ∆CT = 13.5% to 22% over the range of actuation frequencies tested. The corresponding change in rotor power ranged from ∆CP = 2.3% to 6.7%. Frequency analysis performed at multiple radial locations along the rotor blade showed a gradual increase radially in the axial velocity magnitude for all excitation frequencies. The largest axial velocity magnitude corresponded to an actuation frequency of f = 0.2/rev for all radial locations. The numerical results showed a consistent under-prediction at all outboard radial locations, but showed closer agreement to the measured data at inboard radial locations.
Funding Sponsor
U.S. Army
Department
Research Foundation
Recommended Citation
Patrick Mortimer, Daniel Yu, Jayant Sirohi, Jimmy Ho, Mark Lopez, and Ashwani Padthe. "Characterization of the Response of a Single Rotor in Hover to Dynamic Collective Pitch" FORUM 2023 - Vertical Flight Society 79th Annual Forum and Technology Display (2023).
