SlotJet¶

class acoular.environments.SlotJet¶

Bases: FlowField

Analytical approximation of the flow field of a slot jet.

This class provides an analytical model of the velocity field for a slot jet, based on the description in [2]. It describes the flow field originating from a slot nozzle, including the jet core and shear layer, and calculates the velocity field and its Jacobian matrix at a given location.

Notes

• The slot jet is divided into two regions: the jet core and the shear layer. The model distinguishes between these regions based on the non-dimensionalized distance from the slot exit plane.

• The flow field is aligned with the direction of the flow vector, while the plane vector helps define the orientation of the slot.

v0 = Float(0.0, desc='exit velocity')¶

Exit velocity at the slot jet origin (nozzle). Default is 0.0.

origin = CArray(dtype=float64, shape=(3,), value=array((0.0, 0.0, 0.0)), desc='center of nozzle')¶

The location of the slot nozzle center. Default is (0.0, 0.0, 0.0).

flow = CArray(dtype=float64, shape=(3,), value=array((1.0, 0.0, 0.0)), desc='flow direction')¶

Unit vector representing the flow direction. Default is (1.0, 0.0, 0.0).

plane = CArray(dtype=float64, shape=(3,), value=array((0.0, 1.0, 0.0)), desc='slot center line direction')¶

Unit vector parallel to the slot center plane, used to define the slot orientation. Default is (0.0, 1.0, 0.0).

B = Float(0.2, desc='nozzle diameter')¶

Width of the slot (slot diameter). Default is 0.2.

l = Float(5.2, desc='flow establishment length')  # noqa: E741¶

Non-dimensional length of the zone of flow establishment (jet core length). Default is 5.2.

digest = Property( …¶

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

v(xx)¶

Compute the velocity field and its Jacobian matrix at a given location.

This method provides the velocity vector and its Jacobian matrix at the given location xx in the fluid. The velocity is computed for the flow component in the direction of the slot jet, while the entrainment components are assumed to be zero.

Parameters:

xxnumpy.ndarray of floats

The 3D Cartesian coordinates of the location in the fluid where the velocity field is to be computed, shape (3,).

Returns:

velocity_vectornumpy.ndarray of floats

The velocity vector at the given location, shape (3,).

jacobian_matrixnumpy.ndarray of floats

The Jacobian matrix of the velocity vector field at the given location, shape (3,).

Notes

• The velocity field is computed using a local coordinate system aligned with the flow direction and the slot orientation.

• The velocity profile depends on whether the point lies within the jet core region or in the shear layer. In the jet core, the velocity is constant, while in the shear layer, it decays following a Gaussian distribution.

• The Jacobian matrix provides the partial derivatives of the velocity vector components with respect to the spatial coordinates.