Some Methods for Diagnostics of Wake-Induced Laminar-Turbulent Transition

To create a reliable engineering method for calculating local heat transfer of turbine blades, information about the flow regime on the blade surface is necessary. The presence of a wake-induced laminar-turbulent transition on the surface of the blade requires the development of methods for its diagnostics. The object of the study is blade surface under the influence of unsteady periodic wakes from upstream blade rows. The research method is physical modeling of a wake-induced transition initiated by steady wakes behind a still and periodic unsteady wake behind an oscillating cylinder. The article considers some methods for determining the coordinates and extent of a wake-induced transition region. Reliable diagnostics of such a transition is possible only with the help of a combination of developed methods. The presented experimental data allow us to predict the location of a wake-induced transition and the intensification of heat transfer in the preceding pseudolaminar boundary layer, that is, to control the process of such a transition.