A key goal of ACARE and H2020 is the reduction in fuel burn for civil aircraft, leading to reduced environment impact through reduced emissions, both CO2 and NOx. This can be achieved in part by reducing the drag of the aircraft by maintaining laminar flow over a significant extent of the wetted surface. The are two principal ways to do this: Natural Laminar Flow (NLF) and Hybrid Laminar Flow Control (HLFC). The former is achieved through aerodynamic shaping and the latter through a combination of aerodynamic shaping and boundary layer control.
The aim of this project is to design and manufacture a large HLFC half model, representative of a civil transport aircraft wing, for installation in the ONERA S1MA tunnel. The model will be capable of testing the effectiveness of laminar flow control devices at transonic speeds (M~0.85) and high Reynolds number (>10 million/m).
The model will incorporate systems for delaying transition in the leading edge region in two spanwise sections. The outer section will address the HLFC requirements, with active suction through the surface of the porous wing leading edge. The wing will incorporate pipework permitting suction to be applied through the porous surface using a suction source provided by the wind tunnel operator. The location of boundary layer transition across the span will be measured in the experiment using the IR technique and the upper wing surface will therefore include an insulating material for the measurement of transition using IR thermography. As with all HLFC models, the surface finish will be very high quality with no steps or gaps. The suction system and instrumentation will be fully tested prior to delivery of the model. The inboard part of the wing will be equipped with both passive and active (wall suction) anti-contamination devices to investigate ways to control attachment line transition. The model will be fitted with a range of instrumentation including pressure tappings, unsteady pressure transducers, accelerometers, strain gauges and possibly hot films, all of which will be thoroughly tested during final assembly. Finally, on completion of the model assembly, the model deformation due to representative applied static loads will be measured.
