Understanding the prevailing wind patterns of your project site can be useful when it comes to designing ways to take advantage of natural ventilation or to screen occupants from uncomfortable windy conditions. The Project Vasari wind tunnel and wind rose tools allow you to study the local wind conditions and simulate the physical interactions of wind and your design.
Exercise File: 6-0 Wind_Start.rvt: Download this file to follow the exercise.
download video: 06.00-wind.mp4
The wind rose is a versatile tool for visualizing wind patterns for your specific site. You can limit the analysis period by year, season, month, week, or day, allowing you a wide range of controls depending on what is important to your project
Begin by ensuring that you are signed in to your Autodesk account in the upper right-hand area of the Vasari app frame. This enables Vasari to access wind data from a weather file associated with your site.
The next step would be to ensure that you have your site location set correctly and a weather station assigned. You should pick the weather station that is closest to your site. Next, click Analyze tab Climate Analysis panel Ecotect Wind Rose.
The wind rose interface allows you to choose between a number of Google maps underlays. The default mode is set to display yearly average which will allow you to glean the general wind pattern of your site.
Velocity. Wind speed is indicated by the color of the region on the diagram. The units can be toggled at the bottom of the dialog box between Knots, Meters/sec and Km/hr. Unfortunately, there are no settings for imperial units.
Frequency. Each of the rings in the diagram corresponds to a scaled percentage of the analysis time which the wind is blowing at a certain velocity from that specific direction. The frequency reading is along the south axis of the diagram and will scale automatically.
The Wind Tunnel feature can be used with Ecotect Wind Rose analysis to dynamically simulate the impact of wind speed and direction on your projects. This prototype plugin provides a simplified computational fluid dynamics simulation that provides designers and engineers with a virtual wind tunnel to gain an insight on aerodynamic effects early in the design process. Main uses for this tool are:
Begin by clicking Analyze tab Ecotect Wind Tunnel. The wind tunnel tool is a stand-alone module which imports all visible geometry into its analysis environment. If you wish to exclude anything from the wind tunnel analysis, hide it before activating the tool.
There are two ways of controlling the settings for the wind tunnel, either using the compass which hovers in the modeling environment, or using the sliders and toggles on the bar to the left. Like the wind rose tool, the wind tunnel tool only displays in metric units.
Wind Rose. The wind rose associated with your site can be applied to the wind tunnel compass by selecting the Wind Rose check box under Model Display. It will display the current wind rose analysis settings, and updates as you change it.
3D Volumetric. The Wind Tunnel Tool can be set to display data "volumetrically" which shows the impact of wind in three dimensions. The 3D functionality has a number of ways to create wind visualizations, all of which can be toggled under Display settings.
3D Axis. Changing the orientation of the analysis plane from horizontal to a vertical setting will allow you to view wind behavior from an elevation perspective. This can be found in the 3D Axis drop-down menu under the 2D Grid Slice drop-down.
To modify your model geometry based on the airflow simulation, close the Wind Tunnel feature. Then edit your model(s) in the Vasari modeling environment and then reopen the Wind Tunnel tool to iterate the analysis on your revised model geometry. Only visible geometry will be included in the wind analysis, so ensure that only vital geometry is included, otherwise the simulation performance may be affected. Experiment with the calculations and your conceptual models to optimize potential air flow impact
The size and shape of the bounding volume and its relationship with the geometric model can have a significant impact on the calculated air flow. The air flow calculation knows nothing beyond the boundaries of that volume; it is an absolute limit.
If you create a grid that is too close to the side of a model, the air will be artificially squeezed up against that volume boundary. In reality, that air would have been able to expand much further into the space beyond, but instead it is forced through a small gap that will likely result in a localized area of high pressure and artificially increased air speed.
This means that a 2D air flow analysis considers only those parts of the geometry that it actually intersects, and uses only air flow paths that exist within that 2D plane. If any geometry lies slightly outside that plane, both it and its potential turbulence effects are effectively ignored.