Internal pressure modelling for low-rise buildings in tornadoes

Abstract It is well-established that internal pressure can be modelled using the geometric details of the opening and the external pressures near the opening as input. The objective of this study is to determine whether the unique details of tornadic wind fields alter the dynamics of internal pressures, and whether these internal pressures can also be simulated using external pressures at a dominant opening. This is done using measurements from a relatively large-scale tornado simulator for a flow field with multiple sub-vortices, which is expected to be a worst-case scenario for the internal pressure model. These results are then compared to similar studies from atmospheric boundary layer (ABL) wind fields. It is found that the internal pressure model is able to reasonably simulate measured internal pressures in tornadic winds, although not quite as well as in ABL winds. The modelled internal pressure coefficients are mostly within a difference of 0.1 of the measured internal pressure coefficients, which is close to the measurement uncertainty bounds. The reduced accuracy for tornadoes appears to be due to differences in the wind fields in the vortex core of the tornado, particularly the presence of sub-vortices and the vertical component of the wind.