CFD (Computational Fluid Dynamics)
Site Wind Analysis will be undertaken utilising Computational Fluid Dynamics (CFD) software (Phoenics/ Flair). CFD originated in the aeronautics industry but can be applied to the built environment in order to enable assessment of wind effects on buildings in a “virtual wind tunnel”.
The CFD analysis involves creating a 3D representational model of the proposed buildings in the context of their surrounding urban environment and adjacent buildings. Wind profile boundary layers are applied, applicable to urban terrain, for varying wind speeds and directions.
Predicted pressures and velocity vectors in the vicinity of the buildings will be calculated for varying wind speeds and directions, accounting for turbulence effect, with derived parameters determined for Pedestrian Comfort (Lawson Criteria).
CFD enables graphical displaying of coloured contours, vectors and streamlines, allowing complex airflow phenomena to be visualised and understood.
The results of the analysis may be used to inform the landscaping strategy and the positioning of seating to the amenity areas.
Pedestrian Wind Comfort
Pedestrian Wind Comfort will be assessed utilising the “Lawson Criteria” scale, which has been developed as a means of assessing the long term suitability of urban areas for walking or sitting without excessive air movement associated with wind forces. The Lawson Criteria scale ranges from areas deemed suitable for long term sitting through to regions not suitable for pedestrian comfort, as wind effects and associated air velocities would be too excessive for significant periods of the year.
The methodology calculates predicted airflow patterns around buildings for all wind orientations and calculates average velocity applying weighting based on probability of occurrence throughout the year. Therefore, wind effects around buildings for prevailing wind conditions are deemed to have more of a potential impact to pedestrian discomfort, as these will occur on a more regular occurrence.
The long-term annual “Wind Rose” for London as utilised for the Lawson Criteria analysis illustrates the frequency that wind will be from a certain direction and at what speed.
Site Wind Analysis
CFD simulations will be undertaken for the proposed building configuration. Pedestrian comfort will be assessed by predicting Lawson Criteria values at 1.5m above ground level and to other relevant Amenity areas (Roofs/ Balconies etc.).
Our Service to You
We are pleased to be able to offer our clients market-leading Wind Impact Analysis supplied by our own specialised in-house team.
These assessments are carried out in line with current regulations in both Ireland and the UK. This includes the New City of London Wind Microclimate Guidelines (opposite this paragraph).
If you have any questions or require any further information then please contact us.