Isolated propeller aeroacoustics at positive and negative thrust

Using propellers in negative thrust conditions can potentially result in many benefits, such as a steeper descent, a reduced landing run, reduced community noise, energy regeneration, etc. However, the aerodynamics and aeroacoustics of propellers in this regime are not well understood. This paper presents an aeroacoustic analysis of an isolated...

Isolated Propeller Aeroacoustics at Negative Thrust: An Experimental Study

In recent years, there has been renewed interest in propeller research due to environmental concerns. Propellers are known for their low-speed efficiency and compatibility with electric motors. The utilization of regenerative energy during deceleration has been demonstrated to be beneficial for automobiles and has the potential to be applied to...

A wavelet-based separation method for tonal and broadband components of low Reynolds-number propeller noise

Propeller noise generally exhibits a rich mixture of tonal and broadband components related to different physical mechanisms. Specifically, the tones are characterized by having deterministic and persistent characteristics, while the broadband counterpart has random behaviour. The separation is essential for the experimenters as they provide...

Computational aeroacoustics of rotor noise in novel aircraft configurations: A lattice-boltzmann method-based study

The accurate and reliable prediction of the aerodynamic noise sources of open rotors and ducted-fans in electric Vertical Take-Off and Landing (eVTOL) and non-conventional aircraft configurations is a challenging task from a computational perspective. Indeed, such propulsive systems can often operate in highly distorted and non-homogeneous flows...

Efficient low-fidelity aeroacoustic permanence calculation of propellers

A noise footprint prediction framework for propeller-driven aircraft which couples an aerodynamic model and several aeroacoustic models is presented in this study. The aerodynamic model is based on the blade element momentum theory, while the aeroacoustic models are based on a time-domain compact dipole/monopole Ffowcs-Williams and Hawking's...

Assessment of an aircraft propeller noise model by verification and experimental validation

The need to contribute to a sustainable future of the aviation industry has spiked an interest in turboprop engines. This is due to the higher propulsive efficiency, the better take-off and landing performance on short runways, and the new developments in propeller-driven hybrid and electric aircraft. The most significant drawback is the noise...

Improving propeller noise measurement and prediction by applying acoustic imaging

In recent years, there has been a rise of electric propeller aircraft in the field of general aviation. These propeller aircraft greatly reduce the emissions and engine noise compared to conventional aircraft, but noise coming from the propeller stays unchanged. Acoustic imaging, using beamforming, could help in the characterization of...

Investigation of propeller characteristics at low Reynolds number with an angle of attack: A computational aeroacoustic study

Advancements in technology have made commercial unmanned aerial vehicles reliable and readily available, leading to an exponential rise in their market demand over the past few years. COVID-19 has further accelerated this growth through an increase in demand for contact-less delivery and crowd monitoring systems. However,...

Definition of a benchmark for low Reynolds number propeller aeroacoustics

Experimental and numerical results of a propeller of 0.3 m diameter operated at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio ranging from 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics. The corresponding rotational tip...

Development of a Propeller Source Noise Model

Turboprop engines are known for their high fuel efficiency on short-range missions compared to turbofan engines. A disadvantage of turboprop engines is the noise they produce. The dominant noise source of the turboprop engine is the propeller. The goal of this research is to develop a propeller source noise model which has the future goal to...

Impingement of a propeller-slipstream on a leading edge with a flow-permeable insert: A computational aeroacoustic study

This manuscript describes an aeroacoustic computational study on the impingement of a tractor-propeller slipstream on the leading edge of a pylon. Both the flow and acoustic fields are studied for two pylon leading edges: a solid and a flow-permeable one. The computational set-up replicates experiments performed at Delft University of...

Vortex-Surface Interactions: An experimental investigation and the development of a conceptual vortex-surface interaction model

The high efficiency of open rotor propulsion has led to a comeback of propeller propulsion systems in recent years. The main issue preventing wide application of the technology is its high noise level. One of the main contributors to this noise is the pressure fluctuations generated during the interaction between a propeller tip vortex and a...

APIAN-INF: an aerodynamic and aeroacoustic investigation of pylon-interaction effects for pusher propellers

Advanced propellers promise significant fuel-burn savings compared to turbofans. When installed on the fuselage in a pusher configuration, the propeller interacts with the wake of the supporting pylon. This paper presents an experimental analysis of the aerodynamic and aeroacoustic characteristics of this pylon–propeller interaction. An isolated...

The Effects of Pylon Blowing on Pusher Propeller Performance and Noise Emissions

Growing concerns about the environmental impact of aircraft operations and increasing fuel prices have led to the demand for more fuel-efficient aircraft. One of the technologies with the potential to offer a significant reduction in fuel burn is the open rotor engine. However, the noise emissions of such engines are higher than for turbofans,...