Research on the Influence of the Unit Reynold’s Number on the Characteristics of N-Waves at M = 2.5

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This paper presents the results of studying the features of the development of weak shock waves generated by a twodimensional roughness on the wall of the working part of a supersonic wind tunnel in a free flow at a Mach number of 2.5. The measurements were performed with a constant resistance thermoanemometer. It is shown that a twodimensional sticker induces weak shock waves into the free flow. They cause distortion of the average flow, the shape of which corresponds to the N-wave. High-intensity pulsations were recorded in the region of passage of a pair of weak shock waves. With an increase in the unit Reynolds number, the level of distortions of the average flow remains practically constant, but an increase in nonstationary disturbances is observed. It was found that the greatest increase in pulsations caused by Mach waves is observed in the area of the maximum gradient of the average flow. It is found that an increase in the number Re₁ leads to an expansion of the frequency range of unstable disturbances generated by a pair of weak shock waves.

Keywords
experimental studies, supersonic flow, N-wave, unit Reynolds number, thermoanemometer
Funding
The work was carried out within the framework of the Program of Fundamental Scientific Research of the State Academies of Sciences for 2013-2020 (project АААА-А17-117030610125-7). The authors are grateful to the Center for collective use “Mechanics” for the provided equipment
УДК 532.526

Research on the Influence of the Unit Reynold’s Number on the Characteristics of N-Waves at M = 2.5