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Entropy 2018, 20(6), 404; https://doi.org/10.3390/e20060404

Effect of a Roughness Element on the Receptivity of a Hypersonic Boundary Layer over a Blunt Cone Due to Pulse Entropy Disturbance with a Single Frequency

1
College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001, China
2
Beijing Spacecrafts, China Academy of Space Technology, Beijing 100094, China
*
Author to whom correspondence should be addressed.
Received: 23 March 2018 / Revised: 19 May 2018 / Accepted: 23 May 2018 / Published: 24 May 2018
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Abstract

A high-order finite difference method was used to simulate the hypersonic flow field over a blunt cone with different height roughness elements. The unsteady flow field induced by pulse disturbances was analyzed and compared with that under continuous disturbances. The temporal and spatial evolution characteristics of disturbances in the boundary layer were investigated and the propagation of different disturbance modes in the boundary layer was researched through the fast Fourier transform (FFT) method. The effect of the roughness element on the receptivity characteristic of the hypersonic boundary layer under pulse entropy disturbances was explored. The results showed that the different mode disturbances near roughness in the boundary layer were enlarged in the upstream half of the roughness element and suppressed in the downstream half. However, the effect of roughness weakened gradually as the disturbance frequency increased in the boundary layer. A phenomenon of mode competition in the downstream region of the roughness element exited. As the disturbances propagated downstream, the fundamental mode gradually became the dominant mode. A certain promotion effect on the mode competition was induced by the roughness element and the effect was enhanced with the increase in the roughness element height. View Full-Text
Keywords: direct numerical simulation (DNS); pulse entropy disturbances; FFT; hypersonic; receptivity direct numerical simulation (DNS); pulse entropy disturbances; FFT; hypersonic; receptivity
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Wang, Z.; Shi, M.; Tang, X.; Lv, H.; Xu, L. Effect of a Roughness Element on the Receptivity of a Hypersonic Boundary Layer over a Blunt Cone Due to Pulse Entropy Disturbance with a Single Frequency. Entropy 2018, 20, 404.

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