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Effect of Sampling Length on Variation of SPL and Its Effects at Low Frequency

  • Harsh Prateek
  • , B. V. Subrahmanyam
  • , Sanjoy Kumar Saha
  • , M. M. Patil
  • , V. Ashok
  • Vikram Sarabhai Space Center

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Onboard processed flight acoustic data shows large unphysical oscillations in low frequency (5-10 dB oscillations at 50 Hz).Such large oscillations at low frequency are also seen in data obtained from unsteady pressure / acoustic measurements carried out during wind tunnel and static motor firing tests. Our analysis shows that this feature is also seen in synthetically generated random signals. Variation of SPL oscillations with length of time signal (used for processing) has been studied for all the above-mentioned cases. Two common observations have been seen from our analyses. For a given sample length, variation of SPL with time decreases as frequency increases. For a given frequency, variation of SPL with time decreases as sample length increases. It is further noticed that this is a universal feature obtained by processing any signal and can be avoided only by increasing the sample length of the data.

Original languageEnglish
Title of host publicationFluid Mechanics and Fluid Power - Select Proceedings of FMFP 2021
EditorsSuvanjan Bhattacharyya, Himadri Chattopadhyay
PublisherSpringer Science and Business Media Deutschland GmbH
Pages441-446
Number of pages6
ISBN (Print)9789811970542
DOIs
Publication statusPublished - 2023
Externally publishedYes
Event48th National Conference on Fluid Mechanics and Fluid Power, FMFP 2021 - Pilani, India
Duration: 27 Dec 202129 Dec 2021

Publication series

NameLecture Notes in Mechanical Engineering
ISSN (Print)2195-4356
ISSN (Electronic)2195-4364

Conference

Conference48th National Conference on Fluid Mechanics and Fluid Power, FMFP 2021
Country/TerritoryIndia
CityPilani
Period27/12/2129/12/21

Keywords

  • Mach sweep test
  • Power spectral Density (PSD)
  • Sound Pressure Levels (SPL)
  • low frequency
  • oscillations
  • sample length
  • static motor firing test

ASJC Scopus subject areas

  • Automotive Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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