Wake Energy Analysis Method Applied to the Boxprop Propeller Concept
Journal article, 2018

Inspired by Prandtl's theory on aircraft wings with minimum induced drag, the authors have introduced a double-bladed propeller, the Boxprop, intended for high-speed flight. The basic idea is to join the propeller blades pairwise at the tip to decrease tip vortex strength and improve mechanical properties compared to a conventional propeller.

The present work develops a wake analysis method allowing an energy breakdown of the flow as well as making the irreversibility of the flow explicit by using the entropy lost work concept. The method quantifies the strength of flow features such as tip vortices and wakes in terms of engine power. In contrast to existing work, this method removes assumptions of uniform flow, no radial flow, and constant static pressure in the propeller jet.

The results of the wake analysis method can be summarized into three key findings 1) the energy in the tip-vortex of the Boxprop design is comparatively speaking non-existent, 2) the swirl energy level of the Boxprop is higher and this turbomachine is thus more in need of a downstream counter-rotating blade to recover the energy, 3) the Boxprop develops a much larger part of its thrust closer to the hub. Analysis of this aspect of the flow reveals that blade interference approaching the tip, where the blades in a pair are more closely spaced, is quite pronounced. In turn, this indicates that maximum efficiency Boxprop designs are more likely to be obtained by having larger axial separation of the two blades.


Open Rotor


aircraft propeller

wake energy analysis


Computational Fluid Dynamics


Alexandre Capitao Patrao

Chalmers, Mechanics and Maritime Sciences (M2), Fluid Dynamics

Tomas Grönstedt

Chalmers, Mechanics and Maritime Sciences (M2), Fluid Dynamics

Rickard Avellan

GKN Aerospace Sweden

Anders Lundbladh

Chalmers, Mechanics and Maritime Sciences (M2)

Aerospace Science and Technology

1270-9638 (ISSN)

Vol. 79 689-700

Innovativ Framdrivning och Motorinstallation

VINNOVA (2013-01189), 2013-07-01 -- 2017-06-30.

Driving Forces

Sustainable development

Innovation and entrepreneurship

Areas of Advance


Subject Categories

Aerospace Engineering

Vehicle Engineering

Fluid Mechanics and Acoustics


C3SE (Chalmers Centre for Computational Science and Engineering)



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