Comparative study for wind load evaluation using simulation results on simple buildings with flat and duopitched roofs

This study explores how Computational Fluid Dynamics (CFD)–based pressure simulation results can be compared and aligned with wind tunnel experiments and standardized design methods, reflecting the practical process engineers follow when assessing wind loads. The aim is to provide a framework for interpreting and applying simulation outputs with more confidence, supported by a clear workflow. To ensure that the findings are robust and generalizable, the analysis is grounded in a comprehensive parametric dataset: the Tokyo Polytechnic University (TPU) database of isolated low-rise buildings without eaves. This resource contains detailed pressure coefficient data for 116 building models—featuring flat, gable, and hip roofs—tested under eight wind directions, yielding more than 800 individual cases for comparison. To align these wind tunnel tests with the standard procedures the main orthogonal directions were investigated.

Compliance with standards

Before validating CFD results against established references, it is important to set the Eurocode baseline for wind load evaluation. From the wind effect side, a previous article covers how the specific wind profiles are determined and harmonized with the simulations during the preprocess phase, while for wind actions the Eurocode defines two main approaches:

1. Wind pressure on surfaces – expressed through pressure coefficients for a range of building geometries.
2. Wind forces on special structures – i.e. lattice towers.

Since CFD inherently produces surface pressure distributions, this study focuses exclusively on the first approach—wind pressure on surfaces—applied to closed buildings. For the purposes of this comparison, only vertical walls and simple roof types (flat and duopitched) were considered.

Under Eurocode procedures, building surfaces are subdivided into zones whose dimensions are determined by the building’s proportions. In practice, the characteristic zoning length, e , defines the extent of the regions for which local pressure coefficients are specified.

Therefore, to ensure a coherent comparison between wind tunnel tests and simulation results, the mesh refinement must be adjusted accordingly, for each previously presented geometrical case of the dataset for both principal orthogonal directions, which in turn makes a parametric study indispensable.

Parametric methodology

To support the parametric study, a dedicated script was developed to generate results for all three scenarios simultaneously: wind tunnel tests, simulation outputs, and standard-based approaches.