Analysis of Rotor Forces in a Ship Airwake
Abstract
This paper examines the helicopter/ship dynamic interface by combining both experimental and numerical analyses. The flow field over the flight deck of a frigate model was mapped experimentally in a wind tunnel using both stationary and flying hot-film sensors. Using the velocity time-histories measured in the wind tunnel, a numerical representation of the airwake which shares the same spectral characteristics was generated. A blade-element model of the main rotor of a helicopter was then "flown" in this numerical airwake to determine the steady and unsteady loads acting on the rotor. The results of a set of test simulations indicate: 1) that an increase in unsteady rotor loads occurs when spatial cross-correlation functions are included in the generation of the numerical flow field; 2) that the fluctuating vertical velocity has a greater effect on the unsteady rotor loads than the fluctuating horizontal velocity; 3) that the spectra of unsteady forces and moments show similar broadband and resonant behaviour at different free-stream velocities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1994
- Accession Number
- ADA640406
Entities
People
- G. Syms
- S. J. Zan
Organizations
- National Research Council Canada