Validation of Suction Velocity Analysis for Active Laminar Flow Control with Uncertainties

Abstract

This study provides a validation of a recently developed uncertainty quantification methodology for suction velocities with the example of a novel laminar flow control design referred to as a tailored skin single duct (TSSD) panel. The TSSD panel is located on the leading edge of a vertical fin model of an Airbus A320 that is designed to maintain and extend laminar flow over the fin by means of boundary-layer suction. The suction velocities are highly dependent on the local porosity, which is only partly known in practice; therefore, the associated uncertainties need to be quantified. This is achieved by combining experimental and numerical data. The experimental data are based on the wind-tunnel experiments on a full-scale Airbus A320 vertical fin equipped with the TSSD system performed in the large low-speed facility of the German–Dutch Wind Tunnels. The measurements also feature highly accurate mass flow measurements of the integral mass flow through the TSSD system that serve as a validation reference for the uncertainty analysis. Uncertainties are provided for the predicted and the measured total mass flows to validate the proposed method, and a good agreement is obtained. A sensitivity study reveals the most influential contributions to the variance of the computed suction velocities. Depending on the difference between plenum and outer pressure, either uncertainties in the pressure distribution or uncertainties in the porosity parameters dominate the variance of the suction velocity.