GeneralFlowEnvironment¶

class acoular.environments.GeneralFlowEnvironment¶

Bases: Environment

An acoustic environment with a generic flow field.

This class provides the facilities to calculate the travel time (distances) between grid point locations and microphone locations in a generic flow field with non-uniform velocities that depend on the location. The algorithm for the calculation uses a ray-tracing approach that bases on rays cast from every microphone position in multiple directions and traced backwards in time. The result is interpolated within a tetrahedal grid spanned between these rays.

See also

scipy.interpolate.LinearNDInterpolator

Piecewise linear interpolator in N > 1 dimensions.

Examples

>>> import numpy as np
>>> import acoular as ac
>>>
>>> # Instantiate the flow field
>>> flow_field = ac.OpenJet(v0=10.0, D=0.4, l=3.121)
>>>
>>> # Create an instance of GeneralFlowEnvironment
>>> environment = ac.GeneralFlowEnvironment(
...     ff=flow_field,  # Use the custom flow field
...     N=300,  # Number of rays
...     Om=np.pi,  # Maximum solid angle
... )

ff = Instance(FlowField, desc='flow field')¶

The flow field object describing the velocity field, which must be an instance of FlowField.

N = Int(200, desc='number of rays per Om')¶

The number of rays used per solid angle \(\Omega\). Defaults to 200.

Om = Float(pi, desc='maximum solid angle')¶

The maximum solid angle (in steradians) used in the ray-tracing algorithm. Default is numpy.pi.

digest = Property( …¶

A unique identifier based on the environment properties. (read-only)

idict = Dict¶

A dictionary for storing precomputed interpolators to optimize repeated calculations. (internal use)

get_interpolator(roi, x0)¶

Generate an interpolator for ray travel times based on a region of interest.

This method computes the ray trajectories starting from a given microphone position (x0) through a region of interest (roi). The rays’ paths are integrated numerically using a system of differential equations, and the resulting points are used to construct a convex hull. A linear interpolator is then created to estimate travel times for arbitrary points within the region.

Parameters:

roinumpy.ndarray of floats

Array representing the region of interest (ROI), where each column corresponds to a point in the 3D space \((x, y, z)\), shape (3, M).

x0numpy.ndarray of floats

Array representing the location of the microphone in 3D Cartesian coordinates, shape (3,).

Returns:

scipy.interpolate.LinearNDInterpolator object

A linear interpolator object for estimating travel times for 3D positions within the computed ray trajectories.