Accession Number:

ADP005021

Title:

Unsteady Aerodynamics: Application to Helicopter Noise and Vibration Sources,

Descriptive Note:

Corporate Author:

WESTLAND HELICOPTERS LTD YEOVIL (ENGLAND)

Personal Author(s):

Report Date:

1985-11-01

Pagination or Media Count:

10.0

Abstract:

A study was conducted into the feasibility of producing aerodynamic loads of sufficient fidelity to enable a realistic acoustic signal to be derived. The need arises from the excessive bladeslap noise which results from bladevortex interaction. A tool is required to investigate the influence of design and operational parameters as a routine procedure. For this purpose a simplified two dimensional model is developed and validated against a more sophisticated analysis. The model is extended to the rotor application where the complex wake geometry is the determining factor in the character of the loading. From the distributed transient loading an acoustic signal has been derived which has been compared with experimental data. A comprehensive correlation has not yet been performed but the preliminary results are encouraging.

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE