Trailing Edge Noise Prediction Using The Nonlinear Disturbance Equations

Open Access
Author:
Erwin, James Paul
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Kenneth Steven Brentner, Thesis Advisor
  • Philip John Morris, Thesis Advisor
Keywords:
  • computational
  • acoustics
  • prediction
  • edge
  • trailing
  • noise
  • broadband
  • cfd
  • fluid
  • dynamics
Abstract:
Direct computation of broadband noise in reasonable computational times is possible if the calculations can be focused in a specific noise making region of interest. Turbulent boundary layer trailing edge (TBL-TE) noise is of special research interest in the wind turbine aeroacoustic community because, in large scale applications, broadband noise can propagate long distances. A new computational aeroacoustic method is proposed that solves the Nonlinear Disturbance Equations (NLDE) in refined time and spatial scales surrounding the trailing edge of airfoil blades. PSU-WOPWOP is Penn State's noise propagation and prediction software, and it uses the NLDE solution to propagate the acoustic solution to observers. A new NLDE computational fluid dynamics flow solver is presented with validation cases. The Blade Systems Design Study (BSDS) Flatback airfoil section and an NACA 0012 airfoil are tested. Noise is generated due to unsteady laminar vortex shedding and boundary layer interaction, but no TBL-TE noise has been predicted. Turbulence injection techniques have yet to be introduced that allow for the direct computation of TBL-TE noise. For the NLDE tool to be effective in TBL-TE noise prediction, turbulence must be injected at the inflow of the trailing edge computational domain.