Wind rose and urban airflow

The «Wind» tab draws the wind rose from the nearest Dutch weather file and a simulation of airflow between the buildings around the site.

Overview

The «Wind» tab shows the wind rose (observed statistics) and the airflow between buildings (simulation). The airflow shows where wind passes around the site and where it is blocked. It is for concept-stage analysis.

Wind rose

The wind rose collects the hourly wind direction and speed recorded at a weather station, in 16 directions. It contains no modelled values. The data are the TMYx 2011–2025 weather files of climate.onebuilding.org, the standard files of building simulation. Of the Dutch stations, the 39 with a 2011–2025 file are used; older files (for example Ypenburg, 1949–2009) are not.

Station

The nearest station is used. For TU Delft the station is Rotterdam The Hague Airport, about 7 km away (Ypenburg is closer but its record ended in 2009). Other stations include Amsterdam Schiphol, De Bilt, Valkenburg and Hoek van Holland. The wind rose is the wind at the station, not at the site; the screen shows the station name, the distance and the period.

Simulation method

The airflow is computed for one direction: the prevailing direction of the chosen period. The method is the lattice Boltzmann method (LBM) with a Smagorinsky LES turbulence model, run on a GPU, on a fixed 4 m grid. Building heights are the 3DBAG heights used everywhere in the edition. The domain extends 400 m beyond the plate on every side. The simulation accepts radii up to 1 km.

Views

• Wind rose: bar length is frequency, colour steps are speed, the number at the centre is the share of calm
• Plan: colour is speed and the texture shows the flow direction
• 3D: streamlines coloured along their length

Limitations

Data sources

Related guides

• Thermal comfort
• Sun hours
• Data sources

Make diagrams