On the Design of a Methodology for Camber Morphing Optimisation with Noise Reduction

Robert Valldosera Martinez

Key information

Authors:

Robert Valldosera Martinez (Robert Valldosera Martinez)

Supervisors:

Frederico José Prata Rente Reis Afonso (Frederico Afonso); Fernando José Parracho Lau (Fernando José Parracho Lau)

Published in

05/31/2019

Abstract

In order to decrease the emitted airframe noise by a two-dimensional high-lift configuration during take-off and landing performances (NLR7301 with trailing edge flap), a morphing airfoil has been designed through a shape design optimisation procedure starting from a baseline airfoil (NLR7301), with the aim of emulating a high-lift configuration in terms of aerodynamic performances. A methodology has been implemented to accomplish such aerodynamic improvements on the aforementioned baseline airfoil by means of the compressible steady RANS equations at a certain angle of attack, with the objective of maximising its lift coefficient up to equivalent values regarding the high-lift configuration, while respecting the imposed structural constraints to guarantee a realistic optimised design. For such purpose, a gradient-based optimisation through the discrete adjoint method has been undertaken. Once the optimised airfoil is achieved, unsteady simulations have been carried out to obtain surface pressure distributions along a certain time-span to latter serve as the input data for the aeroacoustic prediction framework, based on the Farassat 1A formulation, where the subsequent results for both configurations are post-processed to allow for a comparative analysis. Conclusively, the morphing airfoil has proved to be advantageous in terms of aeroacoustics, in which the noise has been reduced with respect to the conventional high-lift configuration for a comparable lift coefficient, although being penalised by a significant drag coefficient increase due to stall conditions on the morphing airfoil's trailing edge.