Stability of high-speed boundary layer on a sharp cone with localized wall heating or cooling

Soudakov, Vitaly; Федоров, А. В.; Егоров, И. В.

doi:10.1051/eucass/201507569

“…Surface arc actuation can quickly heat the boundary layer [38,42]. According to verified results [43], the wall heating causes the boundary layer to be thick, and local heating makes the transition happen earlier. This seems to be a satisfactory trend, while the perturbation of the plasma to the boundary layer is by no means just a simple temperature change.…”

Section: Discussion Of Control Mechanismsmentioning

confidence: 87%

Experimental study on surface arc plasma actuation-based hypersonic boundary layer transition flow control

Yang¹,

Liang²,

Guo³

et al. 2022

Plasma Sci. Technol.

4

0

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Effective control of hypersonic transition is essential. In order to avoid affecting the structural profile of the aircraft, reduce power consumption and electromagnetic interference, the experiment of low-frequency surface arc plasma disturbance to promote hypersonic transition was carried out in the Φ0.25m double-throat Ludwieg tube wind tunnel of Huazhong University of Science and Technology. The contacting PCB sensors and non-contact focused laser differential interferometry testing technology (FLDI) are used in combination. Experimental results show that the low-frequency surface arc plasma actuation has obvious stimulation effects on the second mode unstable wave and can promote boundary layer transition by changing the spectral characteristics of the second mode unstable wave. At the same time, the plasma actuation can promote the energy exchange between the second mode unstable wave and other unstable waves. Finally, the corresponding control mechanism is discussed preliminarily.

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“…The e N method is a semiempirical method based on LST, which predicts the transition location by accumulating the growth rate of unstable waves [42]. This method is applied to evaluate the transition delay performance by the designed acoustic metasurface.…”

Section: Linear Stability Theorymentioning

confidence: 99%

Broadband design of acoustic metasurfaces for the stabilization of a Mach 4 boundary layer flow

Zhao

¹

,

Liu

²

,

Wen

³

et al. 2022

Adv. Aerodyn.

5

0

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A piecewise acoustic metasurface is designed to suppress the first mode while marginally amplifying the Mack second mode in a Mach 4 flat-plate boundary layer (BL) flow. The results of linear stability theory (LST) and the eN method demonstrate the stabilization effect and transition delay performance, respectively. However, the direct numerical simulation (DNS) results indicate that the designed broadband acoustic metasurface actually weakly excites the first mode with a slightly larger fluctuating pressure amplitude at the surface, which is in contrast to the analysis of LST. The discrepancies are found to lie in the ‘roughness’ effect caused by the recirculation zones inside the microslits and the alternating expansion and compression waves induced at the slit edges, which significantly amplifies the first mode. For further clarification of the competitive mechanism between the acoustic stabilization and ‘roughness’ destabilization effects of metasurfaces on the first mode, a carefully designed metasurface is installed at the maximum growth rate region, which excites the first mode on the metasurface but inhibits its development downstream.

show abstract

“…The e N method is a semiempirical method based on LST, which predicts the transition location by accumulating the growth rate of unstable waves [38]. This method is applied to evaluate the transition delay performance by the designed acoustic metasurface.…”

Section: Fig 1 Schematic Illustration Of the Acoustic Metasurface With Subwavelength Groovesmentioning

confidence: 99%

Broadband Design of Acoustic Metasurfaces for the Stabilization of a Mach 4 Boundary Layer Flow

Zhao

¹

,

Xiao

²

,

Wen

³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

A piecewise acoustic metasurface is designed to suppress the first mode while marginally amplifying the Mack second mode in a Mach 4 flat-plate boundary layer (BL) flow. The results of linear stability theory (LST) and the eN method demonstrate the stabilization effect and transition delay performance, respectively. However, the direct numerical simulation (DNS) results indicate that the designed broadband acoustic metasurface actually weakly excites the first mode with a slightly larger fluctuating pressure amplitude at the surface, which is in contrast to the analysis of LST. The discrepancies are found to lie in the ‘roughness’ effect caused by the recirculation zones inside the microslits and the alternating expansion and compression waves induced at the slit edges, which significantly amplifies the first mode. For further clarification of the competitive mechanism between the acoustic stabilization and ‘roughness’ destabilization effects of metasurfaces on the first mode, a carefully designed metasurface is installed at the maximum growth rate region, which excites the first mode on the metasurface but inhibits its development downstream.

show abstract

Stability of high-speed boundary layer on a sharp cone with localized wall heating or cooling

Cited by 9 publications

References 7 publications

Experimental study on surface arc plasma actuation-based hypersonic boundary layer transition flow control

Experimental study on surface arc plasma actuation-based hypersonic boundary layer transition flow control

Broadband design of acoustic metasurfaces for the stabilization of a Mach 4 boundary layer flow

Broadband Design of Acoustic Metasurfaces for the Stabilization of a Mach 4 Boundary Layer Flow

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