Although the cruise speed of jet powered airliners is below the speed of sound, local regions of airflow around the wing become supersonic – this is referred to as transonic flight. The supersonic region creates a shock wave and as the aircraft speed increases this becomes stronger and produces a rapid rise in aerodynamic drag. Sweeping the wing backwards increases the speed at which this drag rise occurs, but the high wing sweep results in poor low speed performance at take off and landing and a heavier wing. Improving the design of the wing’s aerofoil can also delay the drag rise for the same wing speed so avoiding these penalties.

The tests detailed in this memorandum were conducted as part of the WINDY (WINg Design methodologY) UK R&T program, focused on advancing the fundamental understanding and design methodologies for transonic wings in commercial aviation. The program aimed to provide high-fidelity wind tunnel data to support the development of tools that optimize wing shapes to control shock strength and position, thereby reducing the aerodynamic penalties experienced during transonic cruise.

This wind tunnel campaign targeted the generation of a comprehensive CFD validation dataset based on Airbus aerofoil geometries, extending previous benchmark work with the RAE2822^[1] aerofoil. The experiments were performed at the European Transonic Wind Tunnel pilot facility (pETW) , a scaled environment that replicates the complex flow conditions encountered by airliner wings in transonic flight. The pETW facility offers a Mach number range from 0.15 to 1.3 and Reynolds numbers up to 230 million per meter, enabling accurate simulation of flight-relevant conditions.

By providing precise measurements under controlled conditions, including the use of both solid and slotted wall configurations to mitigate tunnel interference effects, these tests generate a high-quality dataset intended specifically for the validation of CFD codes and aerodynamic prediction methods. This dataset plays a critical role in helping researchers and engineers refine numerical models and wing design strategies. Ultimately, it supports airlines and designers in developing transonic wings that reduce aerodynamic drag, leading to safer, more efficient, and economically viable airliners. The complete dataset provided by Airbus is available for download from the Loughborough University repository in .XML format.

Model Geometry

The test focused on a two-dimensional panel model constructed by joining various aerofoil sections to form a single aerofoil. Although made up of multiple sections, the resulting profile shape closely followed the RAE2822 geometry. Experiments were conducted in the pilot European Transonic Wind Tunnel (pETW) using two wall configurations: one with slotted walls and another with solid walls. The RAE2822 section, characterized by its rear-loaded design and subcritical, roof-top type pressure distribution. Model manufacturing and assembly were carried out by the Aircraft Research Association (ARA). The purpose of the testing was to extend and validate previously obtained data from aerofoils with similar characteristics.

A schematic of the wing section used in the experiment is shown in Figure 1. During testing, two different coordinate system origins were employed for measurement purposes. However, in the dataset presented here, all coordinates have been standardised with the aerofoil’s leading edge as the origin. The streamwise and spanwise directions are denoted as X_A and Y_A, respectively, and have been converted to align with conventional aerodynamic axes. For the reader’s reference, an alternative coordinate system used during wind tunnel measurements can be related to the current one using the transformation, X_WT = -X_A+32. The aerofoil has a chord length of 90 mm and a span length of 270.8 mm, resulting in an aspect ratio (span/chord) of 3. The maximum thickness of the profile is ~11 mm, and the trailing edge thickness is approximately ~0.55 mm.

The aerofoil geometry used in this experiment is available for download here. While the profile is based on the RAE2822 aerofoil, it features a slight modification from the ideal geometry commonly found in external sources such as the NASA database. Specifically, the trailing edge has been altered to accommodate a pressure tapping located at $x/c=100\%$. Therefore, in the current experiment, the trailing edge has a finite thickness of approximately 0.55 mm. This modification is illustrated in Figure 2. The CAD files of the aerofoil and the wind tunnel test section can be downloaded from the complete dataset provided by Airbus.