WIND TUNNEL INVESTIGATION OF THE WING LOAD CONTROL USING SELF-SUPPLYING FLUIDIC DEVICES

Abstract

The wing-load-control systems are developed as a mean to modify a distribution of aerodynamic load on the wing. Such systems are usually used in extraordinary, off-design flow conditions. Particularly, it concerns the reduction of bending loads during accelerated flight manoeuvres or sudden gusts. In such situations, rising bending loads may lead to fatigue damage of the wing. A new concept of active flow control system based on self-supplying blowing devices for the control of the aerodynamic load on aircraft wing was designed in Institute of Aviation and tested in IoA low speed wind tunnel. The study was carried out in the framework of the European project STARLET. The project scope comprises two systems of fluidic control devices: the nozzles blowing air in direction normal and inclined with respect to the upper wing surface, located at 40-70% of wing chord, as classical spoilers, and an alternative system composed of specially designed nozzles located on a modified trailing edge surface. The fluidic control devices were supplied with air from the high-pressure area situated at lower wing surface close to its leading edge. The experimental tests were performed in low speed wind tunnel T-3 (5-meter diameter test section) in the Institute of Aviation. For these tests the model of semi-span wing (2.4 m span) situated vertically on the endplate in wind tunnel test section was used. The model was situated on the two aerodynamic wall balances. To measure the load distribution along the semi-span wing model the 8 strain-gauge bridges were glued to the model front spar, the straingauge bridges were arranged in 14.6% wing chord. Wind tunnel test were performed at Mach number M = 0.1.