underwater.pile_driving_noise

Radiated underwater sound from percussive pile driving (ISO 18406:2017).

Percussive pile driving radiates a train of impulsive acoustic pulses, one per hammer strike. ISO 18406 characterises them with:

• single_strike_sel — the single-strike sound exposure level SEL_ss of one pulse (Formulae 3-4), reusing the 1 µPa²·s reference.
• cumulative_sel / cumulative_sel_identical — the cumulative sound exposure level over N strikes (Formulae 8-9); for N identical strikes SEL_cum = SEL_ss + 10·lg(N).
• pile_strike_metrics — a PileStrikeResult bundling the single-strike SEL, the peak sound pressure level, the SPL/Leq and the 90 %-energy pulse duration for one recorded strike, with a .plot().

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cumulative_sel

cumulative_sel(single_sels: NDArray[np.float64] | list[float]) -> float

Cumulative sound exposure level over N strikes (ISO 18406 Formulae 8-9).

SEL_cum = 10·lg(Σₙ 10^(SELₙ/10)) — the energy sum of the per-strike single-strike SELs.

Parameters

Name	Description
single_sels	Per-strike single-strike SELs, in dB re 1 µPa²·s.

Returns: Cumulative SEL, in dB re 1 µPa²·s.

Raises

Exception	When
ValueError	If the sequence is empty or non-finite.

cumulative_sel_identical

cumulative_sel_identical(sel_ss: float, n_strikes: int) -> float

Cumulative SEL of n_strikes identical strikes: SEL_ss + 10·lg(N).

Parameters

Name	Description
sel_ss	Single-strike SEL, in dB re 1 µPa²·s.
n_strikes	Number of (identical) strikes, N ≥ 1.

Returns: Cumulative SEL, in dB re 1 µPa²·s.

Raises

Exception	When
ValueError	If n_strikes is not a whole number ≥ 1.

pile_strike_metrics

pile_strike_metrics(
    pressure: NDArray[np.float64] | list[float],
    fs: float,
) -> PileStrikeResult

Full per-strike pile-driving metrics (ISO 18406).

Bundles the single-strike SEL, the peak sound pressure level, the SPL/Leq and the 90 %-energy pulse duration of one recorded hammer strike.

Parameters

Name	Description
pressure	Sound-pressure time series of one strike (1-D), in Pa.
fs	Sample rate, in Hz.

Returns: A PileStrikeResult.

Raises

Exception	When
ValueError	If the inputs are invalid.

PileStrikeResult

PileStrikeResult(
    single_strike_sel: float,
    peak_spl: float,
    spl: float,
    pulse_duration: float,
    pressure: NDArray[np.float64],
    fs: float,
)

Per-strike pile-driving metrics (ISO 18406).

Attributes

Name	Description
single_strike_sel	Single-strike SEL, in dB re 1 µPa²·s.
peak_spl	Zero-to-peak sound pressure level, in dB re 1 µPa.
spl	Sound pressure level (Leq over the record), in dB re 1 µPa.
pulse_duration	90 %-energy pulse duration, in s.
pressure	The strike pressure waveform, in Pa.
fs	Sample rate, in Hz.

PileStrikeResult.plot()

PileStrikeResult.plot(
    ax: Axes | None = None,
    *,
    language: str = 'en',
    **kwargs: Any,
) -> Axes | NDArray[Any]

Plot the strike waveform and its cumulative energy.

single_strike_sel

single_strike_sel(
    pressure: NDArray[np.float64] | list[float],
    fs: float,
) -> float

Single-strike sound exposure level SEL_ss (ISO 18406 Formulae 3-4).

The sound exposure level of one hammer-strike pulse, integrated over the pulse, in dB re 1 µPa²·s.

Parameters

Name	Description
pressure	Sound-pressure time series of one strike (1-D), in Pa.
fs	Sample rate, in Hz.

Returns: Single-strike SEL, in dB re 1 µPa²·s.

Raises

Exception	When
ValueError	If the inputs are invalid.