# Wind Speed

![](https://894783789-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPHXQ1I3gb93zpLrLZf%2Fuploads%2Fgit-blob-f5f9514005636979eb4e95422d2f3303914eca4a%2FWind_Speed.png?alt=media)

![](https://894783789-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPHXQ1I3gb93zpLrLZf%2Fuploads%2Fgit-blob-a2bc45cfb43a346001d3b46f7e062cd49ceca9ca%2FWind_Speed.png?alt=media) - [\[source code\]](https://github.com/ladybug-tools/ladybug-grasshopper/blob/master/ladybug_grasshopper/src/LB%20Wind%20Speed.py)

Calculate wind speed at a specific height above the ground for a given terrain type.

By default, the component will calculate wind speed at a height of 1 meter, which is suitable for most thermal comfort models like PET and SET. Alternatively, by hooking up the output wind data to the "LB Wind rose" component, a wind rose for any terrain or at height above the ground can be produced.

This component uses the same wind profile function as used by the "LB Wind Profile" component.

### Inputs

* **met\_wind\_vel \[Required]**

A data collection of meteorological wind speed measured at the *met\_height* with the \_met\_terrian \[m/s]. Typically, this comes from the "LB Import EPW" component. This can also be a number for the meteorological wind speed in m/s.

* **height**

The height above the ground to be evaluated in meters. (Default: 1 meter, which is suitable for most thermal comfort models like PET and SET.).

* **terrain**

Text string that sets the terrain class associated with the output air\_speed. This can also be an integer that codes for the terrain. (Default: city). Must be one the following. 0 = city - 50% of buildings above 21m over a distance of at least 2000m upwind. 1 = suburban - suburbs, wooded areas. 2 = country - open, with scattered objects generally less than 10m high. 3 = water - flat areas downwind of a large water body (max 500m inland).

* **met\_height**

A number for the height above the ground at which the meteorological wind speed is measured in meters. (Default: 10 meters, which is the standard used by most airports and EPW files).

* **met\_terrain**

Text string that sets the terrain class associated with the meteorological wind speed. This can also be an integer that codes for the terrain. (Default: country, which is typical of most airports where wind measurements are taken). Must be one the following. 0 = city - 50% of buildings above 21m over a distance of at least 2000m upwind. 1 = suburban - suburbs, wooded areas. 2 = country - open, with scattered objects generally less than 10m high. 3 = water - flat areas downwind of a large water body (max 500m inland).

* **log\_law**

A boolean to note whether the wind profile should use a logarithmic law to determine wind speeds instead of the default power law, which is used by EnergyPlus. (Default: False).

### Outputs

* **report**

Reports, errors, warnings, etc.

* **air\_speed**

A data collection or single value for the air speed at the input *height* above the ground for the input *terrain*. This can be plugged into thermal comfort models like PET or SET/PMV. Alternatively, by connecting the wind data to the "LB Wind rose" component, a wind rose for the input *terrain* and *height* above the ground can be produced.