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High-frequency low-amplitude signal identification method aimed at high-frequency fluctuating pressure test system

A pressure test, high-frequency pulsation technology, used in aerodynamic testing, character and pattern recognition, testing of machine/structural components, etc., can solve problems such as instability in the second mode, and improve measurement accuracy and application range Effect

Inactive Publication Date: 2018-03-23
CHINA ACAD OF AEROSPACE AERODYNAMICS
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Problems solved by technology

[0003] The technical problem of the present invention is: to overcome the defects of the prior art, to eliminate the high-frequency fluctuation data in the hypersonic boundary layer, which is often subject to broad-spectrum noise, and to extract the second modal unstable wave concerned by the stability test

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  • High-frequency low-amplitude signal identification method aimed at high-frequency fluctuating pressure test system
  • High-frequency low-amplitude signal identification method aimed at high-frequency fluctuating pressure test system
  • High-frequency low-amplitude signal identification method aimed at high-frequency fluctuating pressure test system

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[0077] Such as figure 2 As shown, the schematic diagram of the energy spectral density of the actually measured pulsation signal S'(t) is shown as figure 2 The solid line in , the theoretical energy spectral density of the pulsation signal is as figure 2 As shown by the dotted line, figure 2 The abscissa of is the frequency, the left ordinate is the energy spectral density of the actually measured pulsation signal S'(t), and the right ordinate is the theoretical growth rate of the pulsation signal.

[0078] According to an embodiment of the present invention, the energy spectral density c of the high-frequency low-amplitude signal s The schematic diagram of (t) is as image 3 As shown, the main frequency band of this signal is closest to f 0 , in the example, f 0 = 146.9kHz, c s The energy spectral density of (t) is close to 0.0014.

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Abstract

Provided is a high-frequency low-amplitude signal identification method aimed at a high-frequency fluctuating pressure test system. With dominant frequency of a second modal unstable wave as criterion, signals which are not related to the second modal wave are eliminated by using singular value decomposition and empirical mode decomposition. An implementation mode of the method comprises: firstly,based on energy spectrum density and linear stability theories, determining the dominant frequency of a second modal unstable wave, using the dominant frequency as criterion; then, based on a chaos theory, performing phase-space reconstruction on a one-dimensional pulsation signal, and performing singular value decomposition on a reconstruction matrix, extracting a second modal wave; finally, using empirical mode decomposition, eliminating noise introduced by phase-space reconstruction.

Description

technical field [0001] The invention belongs to a high-frequency low-amplitude signal recognition method for a high-frequency pulsation pressure test system. Background technique [0002] Hypersonic boundary layer transition widely exists in the internal and external flow of aerospace vehicles, which has an important impact on the aerodynamic / thermal load, control efficiency, and propulsion performance of the aircraft. Carrying out hypersonic stability tests and studying the transition mechanism of the boundary layer is an important means to establish a transition prediction method and realize boundary layer control. Second mode instability waves have been shown to dominate boundary layer transitions on simple shapes. Due to the high-frequency and low-amplitude characteristics of the second mode unstable wave, the measurement data of the stability test are often mixed with wind tunnel background noise and instrument electromagnetic noise, and these noises have a wide spectr...

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Application Information

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IPC IPC(8): G06F17/50G06K9/00G01M9/00
CPCG01M9/00G06F30/20G06F2218/00
Inventor 解少飞纪锋汤继斌罗金玲沈清
Owner CHINA ACAD OF AEROSPACE AERODYNAMICS
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