![]() It is also important to include in the model the terrain and the surrounding buildings. It is possible to carry out both the wind loading calculation based on the formula as required by the building regulations and use a CFD model to validate the results, which gives increased confidence in assessing the structural integrity of the building. ![]() While it is worth stressing that the calculation above has to be carried out in order to comply with the relevant building regulations, it is important to complement it with a specific Computational Fluid Dynamics (CFD) analysis, which allows to evaluate the wind load in terms of forces and moments without the limitations listed above. It assumes a constant wind direction without taking into account the extreme flow angularity deriving from a storm and their interaction with the building shape.It does not take into account the terrain shape and the presence of other buildings around the calculated structure, those can potentially affect the flow and ultimately the level of loading on the main structure.The pressure on the building is assumed to be constant, in reality it does vary across the building height and it is most of the times raising towards the top of the structure, therefore in reality the lever arm of the wind load is higher than the one assumed by the previous equation.The Coefficient of Drag \(C_D\) is only assumed and not actually calculated, it can vary substantially as function of the building shape and it is difficult to know from tables as every building shape is different.While this calculation is always required by law in combination with a specified safety factor, it includes a few simplifications: ![]() Where A the area of the building facing directly the wind (frontal area), \(\rho\) is the air density – around 1.2 \(\) – and \(v\) is the wind speed (generally the maximum value recorded at the location of the building) and \(C_D\) is the coefficient of drag, which depends on the shape of the building and is usually given by building regulations. ![]()
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