Horizontal Wind Model

Transform horizontal wind into body-axes coordinates

Library

Environment/Wind

Description

The Horizontal Wind Model block computes the wind velocity in body-axes coordinates.

The wind is specified by wind speed and wind direction in Earth axes. The speed and direction can be constant or variable over time. The direction of the wind is in degrees clockwise from the direction of the Earth x-axis (north). The wind direction is defined as the direction from which the wind is coming. Using the direction cosine matrix (DCM), the wind velocities are transformed into body-axes coordinates.

Dialog Box

Units

Specifies the input and output units:

Units

Wind Speed

Wind Velocity

Metric (MKS)

Meters per second

Meters per second

English (Velocity in ft/s)

Feet per second

Feet per second

English (Velocity in kts)

Knots

Knots

Wind speed source

Specify source of wind speed:

External

Variable wind speed input to block

Internal

Constant wind speed specified in mask

Wind speed at altitude (m/s)

Constant wind speed used if internal wind speed source is selected.

Wind direction source

Specify source of wind direction:

External

Variable wind direction input to block

Internal

Constant wind direction specified in mask

Wind direction at altitude (degrees clockwise from north)

Constant wind direction used if internal wind direction source is selected. The direction of the wind is in degrees clockwise from the direction of the Earth x-axis (north). The wind direction is defined as the direction from which the wind is coming.

Inputs and Outputs

InputDimension TypeDescription

First

 Contains the direction cosine matrix.

Second (Optional)

 Contains the wind speed in selected units.

Third (Optional)

 Contains the wind direction in degrees.

OutputDimension TypeDescription

First

 Contains the wind velocity in body-axes, in selected units.

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