System and method for determining the amplitude of oscillatory instabilities in fluid mechanical devices

Patent metadata

Field	Value
Publication number	US-11573151-B2
Application number	US-201916633657-A
Country	US
Kind code	B2
Filing date	Jul 23, 2019
Priority date	Jul 25, 2018
Publication date	Feb 7, 2023
Grant date	Feb 7, 2023

Abstract

Embodiments herein provide a system (100) to estimate the amplitude of oscillations in a turbulent flow system (102) that exhibits oscillatory instabilities. The system (100) comprises of a sensor (102A) mounted on the turbulent flow system (102) to detect an oscillatory variable in the system obtaining a signal, a signal conditioner (104) that conditions the signal from the sensor, an amplitude estimator (110) that estimates the amplitude of the limit cycle oscillations, and also predict the proximity of the system to the oscillatory instability, a processor (108) connected to the amplitude estimator (110) to compare the predicted oscillation amplitude with a threshold value. The amplitude is estimated by estimating the spectral measure of the time series signal obtained from the system.

First claim

We claim:

1. A system ( 100 ) to determine amplitude of oscillatory instability in a turbulent flow system ( 102 ), the system ( 100 ) comprising:
a processor ( 108 );
a sensor ( 102 A) provided in communication with the processor ( 108 ), configured to obtain at least one signal corresponding to the impending oscillatory instabilities of the turbulent flow system ( 102 );
an amplitude estimator ( 110 ) provided in communication with the sensor ( 102 A) and the processor ( 108 ), wherein the amplitude estimator ( 110 ) includes a spectral measure estimator provided in communication with the processor ( 108 ), wherein the spectral measure estimator is configured to convert the at least one signal into a frequency spectrum, the amplitude estimator ( 110 ) configured to:
estimate an amplitude of the impending oscillatory instabilities by estimating the value of spectral measure of the at least one signal, wherein the spectral measures are calculated based on following equation:

M

f

0
,

Δ
⁢
f

,

f
s

m
,
n
,
x
,
y

=

(

∑

i
=

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Δ

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f
/

f
s

Δ
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f
/

f
s

A
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(

f
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(

i
⋆

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m

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f
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Δ
⁢

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(

f
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(

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wherein A(f) is the amplitude for frequency f in the amplitude spectrum, f o is the frequency of interest where the oscillatory instability is expected, f s is a resolution of the amplitude spectrum and Δf is defined so that [f 0 −Δf, f 0 +Δf] is the range of interest in the amplitude spectrum where the spectral measure is evaluated and m, n, x, y are integers representing the index of the spectral measure; and
detecting oscillatory instability upon the estimated amplitude exceeding a threshold amplitude;
wherein the processor ( 108 ) generates a control signal based on the estimated amplitude that enables an actuator ( 102 B) attached to the turbulent flow system to take control measures.

Assignees

• Indian Inst Tech Madras
• Indian Institute Of Tech Madras Iitm

Inventors

• Pavithran Induja
• Unni Vishnu Rajasekharan
• Varghese Alan John
• Kasthuri Praveen
• Nair Sujith Raman Pillai Indusekharan

Classifications

• G05D19/02

  characterised by the use of electric means · CPC title

• G01M5/0025

  of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence) · CPC title

• G01M5/0008 Primary

  of bridges · CPC title

• G01M15/14

  Testing gas-turbine engines or jet-propulsion engines · CPC title

• G01M5/0066 Primary

  by exciting or detecting vibration or acceleration (vibration testing of structures G01M7/00) · CPC title