Autonomous Systems and Connectivity

Numerical & Experimental Study of Propeller Aeroelasticity (NESPA)

This project focuses on propeller aeroelasticity and more specifically, propeller stall flutter. Stall flutter is seen as a potential hurdle in the progress of turbo-prop designs and may threaten the delivery of new, faster, quieter, and efficient blades. The same problem manifests itself on tilt-rotor blades at high speed, multi-rotor hybrid/electric aircraft and may limit the potential use of RPM-regulated rotor systems. Research in this area is expected to have a strong impact on future aircraft designs.

In order to tackle this problem, the project will involve two linked branches: numerical and experimental studies. The numerical investigation will focus on the blade design, its modelling and simulation using state-of-the-art methods for propeller aerodynamics developed at Glasgow. The idea is to establish the stall flutter envelope and identify the conditions that can be used to demonstrate stall flutter during propeller operation.

The experimental investigation will focus on delivering state-of-the-art data showing the physics of the solid/fluid interaction during flutter, measured at the resolution required for validation of modern aeroelastic simulation methods. To date, there is no such data set available. The use of a large-scale rotor test rig and the availability of several flow diagnostic methods will allow the student to characterize the stalled flow on the blades in great detail and resolved in time. At the same time, measuring the dynamic response of the blade and the evolving blade shape during flutter will allow the student to deliver a unique insight into a complex phenomenon.

Publications

Higgins, R.J., Barakos, G.N., Jinks, E. & Bown, N., (2021) A Propeller Blade Design for Experimental Stall Flutter Investigations, In: 47th European Rotorcraft Forum, Virtual Event, 7-10 Sept. 2021

Higgins, R.J. & Barakos, G.N., (2021) Simulations of installed propellers using HMB3 for the Workshop for Integrated Propeller Prediction (WIPP), In: AIAA Aviation 2021 Forum, Virtual Event, 2-6 Aug. 2021

Installed Propeller Validation (WIPP)

The similarities between the intended rotor rig of Glasgow and the Workshop for Integrated Propeller Propulsion (WIPP) allowed for a validation process to be conducted on a tip-mounted propeller. WIPP was a collaboration between Helden Aerospace, Empirical Systems Aerospace and NASA to provide a comprehensive set of test data that could be used for tip-mounted propeller validation of CFD. The study was conducted at the Lockheed Martin Low-Speed Wind Tunnel (LSWT) using the NASA X-57 wing with a C-130 propeller. The experimental data set included surface pressure coefficients along the wing, overall geometry loads and wake survey data behind the propeller across a range of conditions. For an overview of this validation process, please see the linked video below.

 AIAA Aviation 2021 Presentation, R.J. Higgins

Although the results compare well, more work can still be done to improve certain correlations and to extract greater information. In addition to the direct comparisons to the experiment, we are open to further code-to-code collaborations to explore this test case further.