Effects of Elasticity on Aeroacoustic Performance of Low-Noise Swept Propellers

The aviation industry requires continuous reductions in greenhouse gas and noise emissions, which is resulting in a shift towards hybrid and fully electric aircraft. The propeller is an attractive form of propulsion system for electric aircraft as it can achieve high efficiencies and has excellent scalability potential. However, a major concern...

Potential flow modelling of boundary layer ingesting configurations

Boundary Layer Ingestion (BLI) is a promising technology for reducing the impact of aviation on the environment. By placing a propulsor on an aircraft such that it ingests the slower moving air within the boundary layer, a decrease in power consumption can be achieved. Evaluating the performance of BLI configurations remains a challenge though....

An evaluation of methods and assumptions used in potential flow modelling of swirl recovery vanes

Various potential flow methods with different assumptions are available to quantify the efficiency increase and thrust provided by a swirl recovery vane (SRV). In this paper, thrust coefficients and efficiency results obtained by different potential flow methods for the same SRV geometry at different advance ratios are presented. The methods...

Design of swirl recovery vanes in a slipstream of limited extension

The angular momentum or swirl in the propeller slipstream is an energy loss. An effective method to recover the swirl and increase the propulsive efficiency is to use Swirl Recovery Vanes (SRVs). Former research showed an over-prediction in SRV thrust by a lifting line theory (LLT) model compared to wind tunnel experiments. The LLT model assumes...

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...

Impact of Blade Sweep on Aerodynamic and Aeroacoustic Performance Optimization of Isolated Propellers

Due to the rising demand for short-range air travel and the desire for aircraft driven by electric propulsion, there has been a renewed interest in propeller research. Despite the high potential aerodynamic efficiency of propellers, their excessive noise emissions prevent a widespread use on aircraft. A gradient based optimization study is...

Propeller Slipstream Correction for Wind Tunnel Applications: A panel method approach to model propeller induced rotational flow for aircrafts in mid/high thrust condition

In the post processing of acquired wind tunnel force measurements, propeller-driven aircrafts need a preliminary correction of the propeller slipstream. Propeller slipstream effect has two major contributions to the flow field. The first one is the increase in dynamic pressure and the second is the addition of rotation in the flow field. Without...

External Flow Effects in the Engine/Airframe Integration Testing Technique: A New Thrust/Drag Bookkeeping Approach at the German-Dutch Wind Tunnels

The integration of the engine with the airframe is investigated in the German-Dutch Wind tunnels (DNW) using special scale engines called Turbofan Powered Simulators (TPS). The bookkeeping of thrust and drag must be clear. The TPS thrust is determined under static conditions in a calibration facility, and then subtracted in the wind tunnel test...

The Anti-Fairing: Reducing Drag in Junction Flows

Orthogonal Vortex-Propeller Interaction: Vortex Response and Impact on the Propeller Performance

In some situations, concentrated vorticity which forms a vortical flow is involved in the inflow of a propeller. The impingement of the vortex on the propeller has several detrimental effects, e.g., foreign object damage during ground operation, impact on the propeller performance, unsteady loading on the blade, and tonal noise generation. The...

Design and Analysis of Swirl Recovery Vanes for an Isolated and a Wing Mounted Tractor Propeller

In light of the energy crisis of the early 1970's, NASA and industry gained a renewed interest in high-speed propellers for improved propulsive efficiency and explored the idea of swirl recovery vanes (SRV) to generate a net thrust from the residual swirl in the propeller slipstream. After this first effort on the aerial application of SRV, only...

The influence of laminar-turbulent transition on the perfomance of a propeller

The influence of laminar-turbulent transition on a propeller blade’s performance has been investigated in this study, both numerically and experimentally. The computational fluid dynamics (CFD) is performed using the TAU code developed by the German Aerospace Center, as well as an existing propeller lifting-line code. The laminar-turbulent...

Flap Side-Edge Noise Reduction

Inlet Distortion Characterization of the Boundary Layer Ingesting D8 Aircraft

This thesis experimentally assesses the inflow towards the propulsors and the pressure distribution at the propulsor fan-face for the boundary layer ingesting D8 aircraft, and examines the dependence of the model, the propulsor and the flight condition on the inlet distortion. Use is made of mini-tuft flow visualization and five hole probe...

Experimental and numerical study on wingtip mounted propellers for low aspect ratio UAV design

The effects of the propulsion element in a propeller-driven aircraft are of paramount importance to the overall performance, stability and control characteristics of the system. Positioning the propeller at the wing's tip has been shown to improve the aerodynamic behavior of the aircraft. The complexity of the ow field associated with such a...