# A Parametric Study of Wind Pressure Distribution on Facades Using Computational Fluid Dynamics
###### Abstract  
This paper uses Computational Fluid Dynamics (CFD) to determine wind pressures on facades for the purpose of efficient design of these elements. An outstand fin arrangement was modeled where local brackets are used to protrude the fins from the building. A parametric study, for both changes in the length of the bracket and the fin, was derived from CFD simulations with 1-in-50-year storm conditions adopted throughout. Further simulations are performed for revised wind directions that ensure all fins are equally exposed to oncoming winds. In total, 15 models are created to act as a representative sample of the total number of possible configurations. Peak values for pressure are used to calculate forces and moments on the fins. These wind loading results were then used to interpolate the values for the remaining facade geometries. From interpreting the trends that are apparent in the relationship of fin size and bracket length to efficient loading, a set of design criteria is established. The optimal facade design is defined, based on placing equal importance onto minimizing the force along the fin's length and the moment acting at the fin-bracket connection. The performance of some facade elements is shown to worsen the effects of the wind, relative to other designs, with the potential for very negative consequences. Wind direction is shown to have a significant effect on loading, with the magnitude of wind pressures reduced considerably for the worst affected fin, if the sheltering effect is absent between the fins. wind; loading; pressure; facade; computational fluid dynamics; parametric study 2020  
a significant advancement in the calculation of wind pressures due to facade geometry, with a detailed CFD modeling approach [4]. A 3D steady RANS CFD was used to calculate the mean wind pressures modeled for a mid-rise building both with and without balconies. These dimensions and scale used in the modeling replicated that which was used in previous wind tunnel tests for the purposes of validation. It was found that balconies create a more complex flow and there were significant variations in wind pressures on the windward building facade. In recent times, an extensive resource of best practice guidance has become established for the use of CFD in computational wind engineering. These were first established by [PERSON] and [PERSON] [5] for general use in industrial CFD applications. [PERSON] and [PERSON] [6] present substantive work on how to approach microscale obstacle-accommodating meteorological models. This study highlights concerns over providing an adequate extent for the computational domain as well recommended boundary conditions, specifically relating the effects of wind on buildings in the urban built environment. The following year, [PERSON] et al. [7] performed a similar study for the context of the pedestrian environment around buildings that used high-quality wind-tunnel measurements to develop a best practice approach. Results obtained from CFD modeling are often regarded as insufficient without further validation [8] through full-scale field measurements or wind tunnel testing. However, the availability of validation data is limited as wind-tunnel data in existing literature tends to suit more generic problems [3]. To date, studies that have investigated wind pressure distributions on facades have largely been based on simple facade and building geometries. There has been limited guidance available for more complex designs that are typical in the building industry. There has also been little scope for analyzing features, such as facade details, as computational demands were already significant for the models involved [9; 10]. Furthermore, there has been limited research into the effects of oblique flow which is much more complex than for wind acting in the normal/perpendicular direction [4]. The benefits, therefore, of a parametric study using of CFD modeling for efficient design of facade elements become apparent.