Advanced Acoustic Model 2.4.x Supplemental Documentation 1/12 Octave Band and Pearls on Strings Implementation
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Advanced Acoustic Model 2.4.x Supplemental Documentation 1/12 Octave Band and Pearls on Strings Implementation

Filetype[PDF-1.48 MB]

  • English

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      This Memorandum describes the Pearls on Strings implementation in the Advanced Acoustic Model (AAM) Version 2.4.0 as funded by Uber under Volpe Agreement VPK9A1. This feature allows for mixed fidelity time step analysis to facilitate periodic computation of Time Varying Loudness (TVL) for eVTOL vehicles using a 1/12 Octave Band (OB) analysis. The motivation behind the addition of the Pearls on Strings and full implementation of 1/12 OB capabilities in AAM is as follows:

      • eVTOL acoustic analysis necessitates the use of the Narrow Band Capabilities with 1/12 OB center band frequencies to facilitate research into community acceptability and evaluation of suitable analysis parameters and audibility metrics including TVL. The 1/12 OBs are modeled as narrow bands in AAM, leveraging and extending the existing functionality of the tool.

      • Continuous high frequency time sample rate propagation modeling is not needed for this construct, so the AAM Pearls on Strings analysis mode was conceived that includes hybrid micro and macro time based modeling in the AAM trajectory. This improves computational efficiency by reducing run time and memory requirements, and permits the calculation of full flight operations.

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