TsAGI Developed a Concept of Aircraft Wing Surface Micro-Relief

http://tsagi.ru/en/pressroom/news/5156/ 

During unfavorable weather conditions or in case of crew errors, the flying aircraft risks reaching critical angles of attack, which can lead to a plane crash. To solve the problem of the drop in lift, scientists from the Central Aerohydrodynamic Institute named after Professor N.E. Zhukovsky (part of the Research Center "Institute named after N.E. Zhukovsky") investigate the possibility to control the detachable flow around the wing using the surface microrelief. The fundamental activity is being carried out within the framework of Micro-Relief, TsAGI R&D

At the first stage, TsAGI created a concept of the micro-relief which is a number of plastic-foil zig-zag vortex generators distributed above the streamlined surface.

After that, TsAGI used the subsonic T-129 WT to find the best relief position on the wing. The wing model tests were performed at 15-20 m/s flow rate, 0...35-degree angles of attack, and with different micro-relief positions.

'The testing revealed that wing leading edge area is the most effective position for the micro-relief. This does not only increase the maximum lift coefficient but also significantly slows the lift descent at post stall,' said Maksim Ustinov, Doctor of Sciences in Physics and Mathematics, TsAGI Deputy Head of Supersonic Aircraft Aerothermodynamics.

The next stage included tests of micro-relief influence on high-lift wing; they showed the efficiency of using it at the wing slat.

The concept developed may be applicable for different aircraft types; this year, it will be tested on a main rotor blade model. Tests will be carried out on the special facility in the Department for Rotorcraft Aerodynamics and Dynamics.

In the course of the work, the scientists will study the mechanism of the influence of the relief on the unsteady separation of the flow. This will improve the know-how parameters to be used on the rotor blade profile. It is expected that the use of microrelief will significantly increase the helicopter aerodynamic characteristics, in particular, its maximum velocity.