Aeroacoustic Interface

Aeroacoustic Interface#

The Aeroacustic analysis interface provides comprehensive tools for analyzing acoustic data through various representations and processing methods.

Available Plots#

View Type

Description

Spectra

Frequency-domain representation of acoustic signals.

OASPL

Overall Sound Pressure Level analysis across frequency spectrum. To download the OASPL file, click on three dots next to plot type.

Pressure-time history

Temporal evolution of pressure fluctuations at the location of the observer.

Harmonic content

SPL values at the harmonic frequency and its associates. To download the tonal OASPL file, click on three dots next to plot type when Harmonic content is selected.

Thickness and loading component

Thickness, loading and total pressure components.

Processing Options#

Observers#

List of selectable observers based on their group for which the analysis will be performed.

Boundaries#

List of selectable boundaries for which the analysis will be performed. Total is selected by default and refers to the aggregate of all boundaries.

Frequency Range#

Parameter

Description

Default Range

Frequency range

Range of frequencies to perform the analysis

10 - 10000

Averaging Settings#

Option

Description

Number of segments

Number of segments used for averaging

Segmentation method

Method for dividing the signal into multiple segments for averaging: RPM-based or Time interval-based

Signal Processing Options#

Option

Description

Use 1/3 octave band

Apply 1/3 octave band filtering for frequency analysis

Use A-weighting

Apply A-weighting curve to better represent human hearing perception

Welch method

Apply Welch method for calculating spectra

Welch Method Parameters#

Parameter

Description

Options

Segment length

Length of segments for Welch’s method analysis

None or user-specified value

Scaling

Scaling method for power spectrum calculation

Spectrum, Density

Average

Statistical method for averaging across segments

Mean, Median

Detailed Descriptions#

Frequency Range Configuration#

The frequency range setting determines the span of frequencies included in the acoustic analysis:

  • Default range: 10 Hz to 10000 Hz

Note: This range is used for the analysis, not just the display.

Averaging Configuration#

The averaging system allows for detailed control over how the acoustic data is processed:

  • Default segments: 1

  • Segmentation options:

    • RPM-based: Suitable for rotating machinery analysis

    • Time interval-based: General purpose, with configurable time step

Welch Method Settings#

It can be used for calculating spectra.

  • Segment length options:

    • None: Automatic segment length determination (default)

    • Value: User-specified custom segment length

  • Scaling options:

    • Spectrum: Power spectrum scaling (default)

    • Density: Power spectral density scaling

  • Averaging methods:

    • Mean: Arithmetic mean across segments (default)

    • Median: Median value across segments

💡 Tips

  • Use A-weighting to reflect how humans perceive noise.

  • Use options to improve comparison between observers and to validate results against experimental data.

  • Use different types of analysis for comparison to identify potential sources of noise.

  • Compare different types of analysis to qualitatively differentiate between deterministic and non-deterministic types of noise.

❓ Frequently Asked Questions

  • What is the recommended number of segments for averaging?

    The default value of 1 segment calculates the average across all segments. The number of segments for averaging should be chosen to ensure each segment contains sufficient data to resolve the highest frequency of interest for a representative, continuously averaged signal. As a guideline, the total number of data after averaging should contain at least twice the frequency of interest.

  • When should I use A-weighting?

    Apply A-weighting when comparing results to human perception or when meeting certification requirements that specify A-weighted sound levels.

  • What is the difference between RPM and Time interval segmentation?

    RPM-based segmentation is useful for rotating machinery analysis, where one revolution is used to segment unsteady data. Time-interval segmentation is more general and applicable to all unsteady simulations. Note that when using time-interval segmentation, the interval must NOT be smaller than the simulation time step.

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