Contribution of Swirl Recovery to the Induced Drag of a Propeller-Wing System – A Parametric Study

Contribution of Swirl Recovery to the Induced Drag of a Propeller-Wing System – A Parametric Study

Nederlof, R. (TU Delft Flight Performance and Propulsion)
Kooij, R.N.F. (Student TU Delft)
Veldhuis, L.L.M. (TU Delft Flow Physics and Technology)
Sinnige, T. (TU Delft Flight Performance and Propulsion)

Flow Physics and Technology

2023

With the rise of distributed propeller concepts, there is an increased interest in quantifying the interaction between propeller slipstream and wing. It is known from literature that the local upwash induced by the propeller swirl can lead to a reduction of the wing-induced drag, a phenomenon often referred to as swirl recovery. However, at the same time, the distortion of the lift distribution due to the slipstream interaction cancels part of the swirl recovery benefit. These two separate mechanisms are often grouped together, but their relative contribution to the change in induced drag of a propeller-wing system is unknown. The goal of this paper is to separate the two mechanisms and to quantify their relative importance in terms of the induced drag of a wing immersed in a propeller slipstream. To this end, an improved approach for fast low-order modeling of the interaction between propeller and wing was implemented. The propeller performance is calculated using a BEM model, after which the induced velocities in the slipstream are modeled using a slipstream tube model. The propeller-induced velocities then have been implemented into a vortex-lattice analysis of the wing, including an often overlooked correction for the finite slipstream height experienced by the wing sections immersed in the propeller slipstream. It was found that the tip-mounted configuration with an inboard-up rotating propeller showed the largest reduction in total induced drag, even though the spanwise lift distribution was disturbed the most compared to other spanwise propeller positions. The swirl-induced drag mechanism outweighs the trailing vortex-induced drag mechanism. This is also true when the propeller is rotating in the other direction, when the largest performance degradation is obtained for the tip-mounted configuration.

http://resolver.tudelft.nl/uuid:5240cddf-e898-48f5-89b9-a0c803ddd359

https://doi.org/10.2514/6.2023-3543

American Institute of Aeronautics and Astronautics Inc. (AIAA)

978-1-62410-704-7

AIAA AVIATION 2023 Forum

AIAA AVIATION 2023 Forum, 2023-06-12 → 2023-06-16, San Diego, United States

Institutional Repository

conference paper

© 2023 R. Nederlof, R.N.F. Kooij, L.L.M. Veldhuis, T. Sinnige