Evaluation of the Impact of the Aerodynamic Balance on an Airplane Wing through Computational Fluid Dynamics

Accurately describing and analyzing airplane wing aerodynamics is fundamental to assessing-flight performance. Computational and scaled experimental studies are usually employed in order to obtain detailed information of the aerodynamic performance of wing geometry models before full-scale tests. This is usually done first in low-speed wind-tunnels, where the wing is connected to a balance that measures the aerodynamic forces on the wing. The flow around wings is complex and highly dependent on the wind speed and turbulence levels, and these complexities are usually increased by the presence of the balance arm in the wind tunnel, which is necessary for the measurements. Computational fluid dynamics (CFD) is a powerful simulation tool that can be used to predict external flow aerodynamics around wind-tunnel models, in which the geometry can be modified to match exactly the wind tunnel models and the coupling with the balance arm. In this work, the commercial software ANSYS CFX is used to investigate the flow around a floatplane wing attached to a wind tunnel balance arm in order to assess the influence of the balance arm in the aerodynamic measurements on the wing and develop correction parameters to isolate the forces on the wing without the influence of the balance arm. Both the numerical and experimental results show that the subtractive correction requires a corrective factor in the lift and drag coefficients for better alignment with the wing-only condition.