STUDY OF ACTIVE ROTOR CONTROL FOR IN-PLANE ROTOR NOISE REDUCTION

Open Access
Author:
Yang, Tianxiao
Graduate Program:
Aerospace Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
October 10, 2016
Committee Members:
  • Kenneth S. Brentner, Dissertation Advisor
  • Kenneth S. Brentner, Committee Chair
  • Mark D. Maughmer, Committee Member
  • Sven Schmitz, Committee Member
  • Anthony A. Atchley, Outside Member
Keywords:
  • rotor noise
  • noise reduction
  • active control
Abstract:
This research consists of two parts: the main part of this research is the study of active rotor control for in-plane rotor noise reduction. In this study, methodologies to find a loading solution (for point control force) that results in in-plane noise reduction have been developed. Noise reduction at a single observer and over an area (multiple observers) were both discussed. Additionally, two active devices were proposed for in-plane noise reduction. Specifically, an active flap is used to generate chordwise force to reduce in-plane noise, while a rotating winglet is proposed to generate spanwise force for noise reduction. Another part of this research is the study of thickness noise prediction method. A new thickness noise prediction method (dual compact thickness noise model) has been developed. This dual compact model has been validated through thickness noise computation for a wide variety of cases, in which different airfoils, blade planforms, and tip Mach numbers, were considered. The computation time was significantly reduced by using the dual compact model as compared to the normal thickness noise computation (typically 25 times faster).