高超声速导流罩锥台上的线性和非线性扰动演化
Linear and Nonlinear Disturbance Evolution on the Frustum of Hypersonic Ogive-Cylinders
摘要：
本文通过考虑在尖拱-圆柱交界面下游不同位置处自由振荡随机和波包强迫的线性和非线性扰动演化，阐明了马赫数~ $6$下$14^{\circ}$尖拱-圆柱转捩机制的若干方面。随机强迫的光谱响应显示有利的协议与AFRL的实验观测配置的基础上。间歇性波包是由小振幅连续自由振荡压力强迫产生的。线性波包演化表明，Mack模式是主要的初级不稳定性，其次是相对较弱的第一模式波。非线性波包显示了三腿壁压扰动签名，这是追溯到展向曲率效应，和基本共振是占主导地位的二次不稳定机制。在较高的激励振幅，弱签名的次谐波和斜共振现象被识别。小振幅扰动的下游位置减小了第一模式波的感受性;然而，在高振幅强迫下，致动的位置不会显著改变扰动演化特征或二次不稳定机制。
英文摘要：
Aspects of transition mechanisms on a $14^{\circ}$ sharp-nosed ogive-cylinder at Mach~$6$ are elucidated by considering linear and nonlinear disturbance evolution of freestream stochastic and wave packet forcing at different locations downstream of the ogive-cylinder junction. The spectral response of the stochastic forcing displays favorable agreement with experimental observations from AFRL on which the configuration is based. Intermittent wave packets are generated from small-amplitude continuous freestream pressure forcing. Linear wave packet evolution reveals that Mack modes are the dominant primary instabilities, followed by relatively weaker first-mode waves. The non-linear wavepacket displays a three-legged wall pressure perturbation signature, which is traced to spanwise curvature effects, and fundamental resonance is the dominant secondary instability mechanism. At higher amplitudes of excitation, weak signatures of sub-harmonic and oblique resonance phenomena are identified. Downstream placement of the small-amplitude disturbance diminishes receptivity of first-mode waves; however, with high-amplitude forcing, the location of actuation does not significantly vary the disturbance evolution signature or the secondary instability mechanisms.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
