Airflow through net covered tunnel structures at high wind speeds

The airflow around and through net covered tunnel structures was experimentally and numerically analysed for wind speeds above 10 m s−1. A full scale tunnel structure covered with four different nets, characterised by different aerodynamic properties, was built. Wind speed was measured outside and inside the structure by means of two handheld rotary-cup anemometers. The same structure has been numerically analysed by two-dimensional Computational Fluid Dynamics (CFD) simulations where the net is modelled as a porous medium obeying the Forchheimerʹs law. Good agreement between full-scale and numerical results was observed. The numerical results were further validated against wind tunnel measurements of the aerodynamic pressure coefficients which are available in the literature. Both full scale experiments and numerical simulations indicate that the internal air velocity depends on the aerodynamic resistance coefficient of the net, rather than its solidity ratio.