When evaluating criteria for individual force coefficients as integral quantities, it is important to note that integration processes in the evaluation typically reduce numerical errors. The accuracy requirements should be based on the significance of the result classes, with force coefficients arising from pressure differences and thus being independent of absolute pressure.
The Eurocode EN 1990 implies a model factor of 1.05 to 1.15 for inaccuracies in load assumptions. This suggests that force coefficients should lie within this range or be adjusted accordingly. It should be noted that validation cases (such as wind tunnel tests) also contain uncertainties.
For values perpendicular to the wind direction, where mean values are close to zero, standard deviation or peak values are decisive. Characteristic peak coefficients require an extreme value analysis, which is sensitive to outliers. A seemingly plausible force coefficient that is randomly achieved without a validated pressure basis does not constitute sufficient validation.
Pressure coefficients are limited to 1.0 according to Bernoulli’s principle, while suction coefficients can vary up to -10.0 or more. Instead of focusing on individual maximum values, a broader statistical consideration should be conducted, as described in the following section.