METHODS FOR DETERMINATING THE LAMINAR-TURBULENT TRANSITION IN THE BOUNDARY LAYER OF A VARIOFORM-SECTIONAL WING

This work is devoted to the estimation of the possibilities of investigating the boundary layer on the varioform-sectional wing with the help of an acoustic sensor and an absolute pressure sensor. The base model was a wing with a rigid wavy surface. In the boundary layer of this model, a large number of measurements were made using the technique of thermoanemometric measurements. The article compares velocity profiles and pulsation profiles obtained with a thermoanemometer and with the help of an acoustic sensor and a pressure sensor. It is shown that the presence or absence of a laminar-turbulent transition (LTP) and a local separation zone (LSZ) can be qualitatively determined with the aid of an acoustic sensor and a pressure sensor. However, quantitatively, the data obtained by different sensors may be different. The difference in the position of the maximum amplitude of pulsations obtained by the thermal anemometer and the microphone sensor differs by 5– 20 % over the chord. This depends on the presence or absence of a local separation zone in the measurement area. The longitudinal component of the average velocity in the boundary layer in the region of the separation zone obtained by the absolute pressure sensor can differ from that obtained by the method of thermal anemometry by 80 %.

Keywords:
low Reynolds numbers, flow around a wing with a wavy surface, varioform sectional wing, boundary layer, separation bubble, laminar-turbulent transition, displacement thickness ,momentum thickness. 
УДК 533.69; 533.6.001.32

METHODS FOR DETERMINATING THE LAMINAR-TURBULENT TRANSITION IN THE BOUNDARY LAYER OF A VARIOFORM-SECTIONAL WING