Wind and Structures

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CFD model validation with experimental tornado wind field & comparison of wind field in different tornado chambers

  • Verma, Sumit (Department of Civil Engineering, University of Arkansas) ;
  • Selvam, Rathinam P. (Department of Civil Engineering, University of Arkansas)
  • Received : 2021.03.03
  • Accepted : 2021.09.23
  • Published : 2021.11.25
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Abstract

Validation of CFD tornado wind field with experimental or field measurements is limited to comparison of tangential velocity profile at certain elevations above the ground level and few studies are based on comparison of pressure profile. However, important tornado vortex features such as touchdown swirl ratio (ST), core radius (rc), maximum tangential velocity (Vtmax), elevation of maximum tangential velocity (zc) and pressure distribution over a range of varying swirl ratios which strongly influences tornado forces on a building have not been accounted for validation of tornado wind field. In this study, important tornado vortex features are identified and validated with experimental measurements; the important tornado features obtained from the CFD model are found to be in reasonable agreement with experimental measurements. Besides, tornado chambers with different geometrical features (such as different outlet size and location and total heights) are used in different works of literature; however, the effect of variation of those key geometrical features on tornado wind field is not very well understood yet. So, in this work, the size of outlet and total height are systematically varied to study the effect on important tornado vortex parameters. Results indicate that reducing outlet diameter in a tornado chamber increases ST, Vtmax and zc and decreases rc. Similarly, increasing total height of tornado chamber decreases ST, Vtmax and rc whereas zc remains nearly constant. Overall, it is found that variation of outlet diameter has a stronger effect on tornado wind field than the variation in total height of tornado chamber.

Keywords

Acknowledgement

The research described in this paper was financially supported by the National Science Foundation under award number CMMI-1762999. The authors appreciate the unknown reviewers' input which helped to improve the paper extensively.

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