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Acoustics Research of Propulsion SystemsThe liftoff phase induces some of the highest acoustic loading over a broad frequency for a launch vehicle. These external acoustic environments are used in the prediction of the internal vibration responses of the vehicle and components. Thus, predicting these liftoff acoustic environments is critical to the design requirements of any launch vehicle but there are challenges. Present liftoff vehicle acoustic environment prediction methods utilize stationary data from previously conducted hold-down tests; i.e. static firings conducted in the 1960's, to generate 1/3 octave band Sound Pressure Level (SPL) spectra. These data sets are used to predict the liftoff acoustic environments for launch vehicles. To facilitate the accuracy and quality of acoustic loading, predictions at liftoff for future launch vehicles such as the Space Launch System (SLS), non-stationary flight data from the Ares I-X were processed in PC-Signal in two forms which included a simulated hold-down phase and the entire launch phase. In conjunction, the Prediction of Acoustic Vehicle Environments (PAVE) program was developed in MATLAB to allow for efficient predictions of sound pressure levels (SPLs) as a function of station number along the vehicle using semiempirical methods. This consisted, initially, of generating the Dimensionless Spectrum Function (DSF) and Dimensionless Source Location (DSL) curves from the Ares I-X flight data. These are then used in the MATLAB program to generate the 1/3 octave band SPL spectra. Concluding results show major differences in SPLs between the hold-down test data and the processed Ares IX flight data making the Ares I-X flight data more practical for future vehicle acoustic environment predictions.
Document ID
20140011603
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Gao, Ximing
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Houston, Janice D.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
September 12, 2014
Publication Date
June 16, 2014
Subject Category
Launch Vehicles And Launch Operations
Report/Patent Number
M13-3088
Meeting Information
Meeting: AIAA/CEAS Aeroacoustics Conference
Location: Atlanta, GA
Country: United States
Start Date: June 16, 2014
End Date: June 20, 2014
Sponsors: American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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