Wind comfort should be assessed at the mean pedestrian level since the comfort criteria is correlated to the wind characteristics at the pedestrian height.
With the Pedestrian comfort map setting, the user can define the desired pedestrian height at which the wind comfort will be evaluated according to the different standard wind comfort criteria.
The setting can be found in the simulation tree as shown below:
Figure 1: Pedestrian comfort map settings in the Workbench
Click on the ‘+’ button, as shown in Figure 1, to create a Pedestrian level. The user needs to specify two primary inputs: the average pedestrian height/level above the ground and the ground type.
Height Above Ground
Figure 2: Average pedestrian height depends on the scenario in hand. People sitting outside a cafe will account for a reduced height.
Height above ground input should be defined by taking average pedestrian height into account. This value varies based on the region of simulation. Evaluating wind comfort outside a cafe where people are sitting or in a kids’ park will have a reduced height value. On the other hand, busy city streets will take up the actual height of an average pedestrian.
The height value can be specified in either meters or inches.
Ground
Ground reference can be either “absolute” (uses bottom of region of interest as reference) or “relative” uses each assignment as reference and elevates those by the height defined.
Absolute
It uses the bottom of the wind tunnel as the reference height. Any value specified will be with respect to this height. The dimensions for the wind tunnel are defined under Advanced settings while setting up the Region of interest.
Figure 3: Absolute Height vs. Relative Height used for defining the Pedestrian comfort map
Relative
Pedestrians can be located at different elevations. In such cases users can select multiple surfaces for the comfort criterion evaluation. The height in this case will be with respect to those selected surfaces.
A schematic of both absolute and relative height references is shown in Figure 2.
Figure 3 is an actual snap from the SimScale Workbench showing the wind comfort criteria at different levels: absolute and relative.
Figure 4: Wind comfort criterion evaluated at both absolute and relative heights. For most of the region (disk) it is absolute 1.75 meters while for the buildings marked within the orange polygon the height is 1.75 meters relative to the top surfaces of the buildings.
Creating Multiple Maps
It is possible to create more than one Pedestrian comfort map within the same setup. This can be useful if one needs to categorize the comfort results based on different absolute and relative heights or faces selected according to different regions of the CAD model.
Wind Comfort Criterion
The wind comfort is evaluated only over the region of interest defined by a cylinder around the main building/s. Everything outside of it is cut off for the result export.
Figure 5: Example of a Wind Comfort Criterion evaluated over the region of interest seen as a disk here, in SimScale.
User can view the results with respect to the following wind comfort criteria:
Lawson
Davenport
Lawson LDDC
Lawson 2001
Lawson LDDC Comfort
NEN8100 Comfort
NEN8100 Danger
Each criterion consists of a threshold value for the wind speed and a maximum allowable exceedance probability of the threshold value. Colors represent the scale of a comfort level with respect to the selected comfort criterion.
Each comfort criterion may lead to different conclusions about the comfort level. Users can quickly switch to a different criterion in order to evaluate as desired.
Figure 6: PWC Simulation with Lawson and Davenport criterion for the same simulation setup and same geometry
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