ACOUSTIC PREDICTION OF HEAVY LIFT ROTOR CONFIGURATIONS USING MOMENTUM SOURCE METHOD

Open Access
Author:
Mohanamuraly, Pavanakumar
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Kenneth Steven Brentner, Thesis Advisor
Keywords:
  • momentum source
  • rotorcraft aeroacoustics
  • actuator model
  • interactional aeroacoustics
Abstract:
Calculating acoustics for a full rotorcraft configuration in the design phase is a challenging task, which requires a numerical approach with the right level of fidelity at low computational cost. In the present work, an actuator line model (ALM) for the rotor is proposed where the individual blades of the rotor are modeled as singular line sources in the governing equation by adding momentum and energy equivalent to the rotor. This model was implemented in a parallel unstructured, finite-volume compressible Euler (UFVS) solver, which uses the Roe approximate Riemann solver for interfacial fluxes calculation and an optional 2nd/4th order Runge-Kutta method for the time integration. Using overset grid methodology the UFVS-ALM solver was embedded into a bigger suite of tools called Immersed Boundary Solver for Environment Noise (IBSEN) such that the rotor near field is modeled using the UFVS-ALM approach and the flow field over other solid bodies like fuselage, wing and other appendages are captured using IBSEN's Cartesian Grid solver. A model isolated rotor in hover with rectangular, un-tapered blades and NACA 0012 airfoil section was used as a test case to validate the standalone UFVS-ALM solver and the overset UFVS-ALM IBSEN numerical approach. The results are validated against experimental values and the predicted flow field and acoustics are qualitatively assessed.