INFLUENCE OF A SURFACE FRACTAL MICROSTRUCTURE ON THE CHARACTERISTICS OF A TURBULENT BOUNDARY LAYER

摘要

The results of startup experimental investigations on the properties of a turbulent boundary layer over flat plates with a chaotic micro- and nanostructure possessing hierarchy of granularity (fractality) are given. Experimental investigations were carried out in the low-turbulent and low-speed aerodynamic T-36I wind tunnel at TsAGI. The samples in the experimental study were flat plates (160 × 160 mm~2) with a fractal surface, which were obtained by high-temperature plasma processing in the fusion device, QSPA-T, of metallic plates that were originally smooth. The influence of the surface fractal microstructure on the velocity spectrum and the structure of the turbulent boundary layer were registered in both load and hot-wire experiments. Suppression of the low-frequency bandwidth of the velocity spectrum and the change in aerodynamic drag were observed, which indicates the possibility of turbulence control.