Russian scientists have developed a matrix of active actuators against turbulence for an airplane wing


    Smart electromechanical and electro-hydraulic actuators with integrated electronics on the Boeing 787-8 control 21 aerodynamic flight control surfaces. Manufacturer: Moog Inc.

    Scientists at St. Petersburg State University and the Institute of Problems of Mechanical Engineering of the Russian Academy of Sciences, with the support of the Russian Science Foundation, have developed an innovative way to combat turbulence in aviation - a system of active plates on the wing of an aircraft that independently change their spatial position depending on air pressure, Izvestia writes .

    The developers propose covering the wing surface with a matrix of active cells, each of which is equipped with a pressure sensor, a microcomputer and a wing plate - a “pen” - with an electric drive. When turbulence occurs, the “feathers” move and change their inclination relative to the wing, compensating for the resulting inhomogeneity of air pressure. In addition, each “pen” exchanges data with neighboring cells, calculating the necessary position.

    In a sense, scientists have spied such a decision on nature. Sharks, killer whales, dolphins and other large marine animals, when swimming at high speed, also begin to vibrate the skin surface, which prevents the movement from moving into a turbulent mode.

    Turbulence is a phenomenon observed in many flows of liquids and gases and consists in the fact that numerous vortices of various sizes form in these flows, as a result of which their hydrodynamic and thermodynamic characteristics (speed, pressure, temperature, density) experience chaotic fluctuations and therefore change over time and space irregularly.

    The problem with turbulence is that it significantly increases the amount of energy needed to move the body. If at low speeds the resistance increases in proportion to the speed, but after exceeding a certain critical value of the Reynolds number, turbulent turbulences begin to form. From this moment, the resistance increases in proportion to the square of the speed. Even a slight increase in speed requires a large expenditure of energy.

    The study of dolphins in a hydrodynamic pipe showed that during movement the fluid flow around the dolphin remains laminar, that is, no turbulent flows arise. As it turned out, when moving in water, folds run through the thick elastic skin of the dolphin. They arise exactly in those momentswhen the surrounding flow is about to turn from laminar to turbulent. It is at this moment that a “traveling wave” appears on the skin, which quenches the resulting turbulence. According to scientists, dolphins reach speeds of up to 54 km / h, after which they turn on the pain threshold.

    Engineers subsequently began to repeat this biological mechanism in shipbuilding, aircraft building, during the construction of oil pipelines, etc. However, active actuators on wings under the control of microcomputers are a fundamentally new level of development.

    “We are not at all trying to eliminate turbulence as such, and this is impossible,” explained Oleg Granichin, project manager, doctor of physical and mathematical sciences, professor of St. Petersburg State University. “We set ourselves another task: to compensate for the pressure difference in different areas of the wing so that the aircraft maintains a stable position in the turbulence zone.”

    A mathematical solution to the project was developed at St. Petersburg State University. The authors of the system say that the solution with a distributed control system was forced: "Even the most powerful modern computer would not have enough speed for centralized control of all cells," said Konstantin Amelin, developer of the mathematical solution, postdoc at St. Petersburg State University.

    The system has already been tested in practice. An experiment in a wind tunnel on a meter wing with a hundred “feathers” showed that the distributed microcomputer system (for some reason Konstantin Amelin compares it with the blockchain) works in concert and finds a consistent solution for each unit of plumage. Now engineers are working to create a more advanced test bench with an operating aircraft model, with a wingspan of two meters, and the “feathers” will be able to rotate in two planes, and not in one, as now.

    Independent experts carefully evaluate the work of colleagues. The fact is that active actuators are far from a new idea. Scientists have experienced a wide variety of technological solutions, but so far no one has proposed a ready-made solution that would compensate for turbulence at high speed, and not just in a narrow speed range.

    Also popular now: