Contra-rotating propellers could increase the efficiency and lifting capacity of multi-rotor
unmanned aerial vehicles (UAVs); however, contra-rotating propellers can produce …

This paper presents a numerical analysis of an airfoil geometry inspired by the down coat of
the night owl. The objective is to understand the mechanisms of airfoil trailing edge noise …

Numerical analysis of airfoil geometries inspired by the down coat of the night owl is
presented. The bioinspired geometry consists of an array of'finlet fences', which is placed …

This study investigates the benefits of noise control for a small-sized contra-rotating (CR) fan
using microperforated-panel (MPP) casing treatments over the rotor. Several configurations …

As propeller-driven aircraft are the best choice for short/middle-haul flights but their acoustic
emissions may require improvements to comply with future noise certification standards, this …

Phased array microphone measurements and beamforming technology have been applied
in the investigation of counter-rotating open rotors in an attempt to better understand their …

Model scale tests of modern 'open rotor'propulsor concepts that have potential for significant
fuel burn reduction for aircraft applications were completed at NASA Glenn Research …

Propeller installation options for a twin-engined turboprop aircraft are evaluated at cruise
conditions, aiming to identify the quieter configuration. Computational fluid dynamics is used …

In the asymptotic theory of propeller noise the far-field noise is dominated by small regions
of the propeller representing interior stationary points or boundary critical points. For contra …

Counter-rotating rotor configurations are considered more efficient than their single rotor
counterparts. Consequently, the coaxially aligned rotors have appeared in the fixed-wing …