Surface pressure measurements in translating tornado-like vortices

Aya Kassab, Chowdhury Jubayer, Arash Ashrafi and Horia Hangan

Abstract

High spatial and temporal surface pressure measurements were carried out in the state-of-the-art tornado simulator, the Wind Engineering, Energy and Environment (WindEEE) Dome, to explore the characteristics of stationary and translating tornado-like vortices (TLV) for a wide range of swirl ratios (S=0.21 to 1.03). The translational speed of the TLV and the surface roughness were varied to examine their effects on tornado ground pressures, wandering, and vortex structure. It was found that wandering is more pronounced at low swirl ratios and has a substantial effect on the peak pressure magnitude for stationary TLV (error percentage≤35%). A new method for removing wandering was proposed which is applicable for a wide range of swirl ratios. For translating TLV, the near-surface part lagged behind the top of the vortex, resulting in a tilt of the tornado vertical axis at higher translating speeds. Also, a veering motion of the tornado base towards the left of the direction of the translation was observed. Wandering was less pronounced for higher translation speeds. Increasing the surface roughness caused an analogous effect as lowering the swirl ratio.

Key Words

roughness; surface pressure; swirl ratio; tilting; tornado-like vortices; translation speed; veering; wandering

Address

Aya Kassab:WindEEE Research Institute, Western University, 2535 Advanced Ave., London, ON, Canada, N6M 0E2 Chowdhury Jubayer:WindEEE Research Institute, Western University, 2535 Advanced Ave., London, ON, Canada, N6M 0E2 Arash Ashrafi:WindEEE Research Institute, Western University, 2535 Advanced Ave., London, ON, Canada, N6M 0E2 Horia Hangan:WindEEE Research Institute, Western University, 2535 Advanced Ave., London, ON, Canada, N6M 0E2

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