Features of the interaction of localized free-stream disturbances with the straight and swept wing boundary layer

M M Katasonov,V V Kozlov,A M Pavlenko,I A Sadovskii

doi:10.1088/1742-6596/1404/1/012092

Abstract

Under the conditions of a model experiment, the features of the appearance and spatial development the boundary layer disturbances – wave packets (precursors) and longitudinal localized structures were studied. Localized disturbances were created artificially upon local exposure of an external source to the boundary layer of the straight and swept wing with a low turbulence level of incoming flow. Wave packets formed near the fronts of longitudinal localized structures. The studies were carried out in a subsonic low-turbulent wind tunnel. Flow perturbations were recorded using a constant-temperature hot-wire anemometer.

Highlights

Laminar-turbulent transition in the boundary layer at a moderate or elevated level of free-stream turbulence is associated with disturbances created by external turbulence
Under controlled conditions, we study the occurrence and spatial development of perturbations of the boundary layer – wave packets and longitudinal banded structures
The disturbance slightly diffuses, in proportion to the increase of the boundary layer thickness, which was noted in a number of previous studies [2, 3], when disturbances were introduced from the model wall [4, 5]

Summary

Introduction

Laminar-turbulent transition in the boundary layer at a moderate or elevated level of free-stream turbulence is associated with disturbances created by external turbulence. According to recent experimental studies [4,5,6], a localized effect on the boundary layer can lead to the appearance of wave packets along with banded structures. Under controlled conditions, we study the occurrence and spatial development of perturbations of the boundary layer – wave packets (precursors) and longitudinal banded structures.

Results

Conclusion