DOI: 10.17603/ds2-gj9q-js65
title: Velocity and Pressure Measurements of the Simulated Tornado-like Vortex
title: in Assessment of Tornado Loading on Low-Rise Buildings Using Computational Modeling and Tornado Simulator Testing

description: The experiments were conducted in a large-scale Ward-type simulator at Texas Tech University known as the VorTECH simulator. A 4-hole Cobra probe (Turbulent Flow Instrumentation Pty Ltd) with a dedicated data acquisition system and a 12-hole Omniprobe (Aeroprobe Corporation) sampled by a Scanivalve pressure scanner were used for the velocity measurements, with these probes chosen for their complementing characteristics. In addition to the velocity measurements, the static pressures at 195 axisymmetric taps evenly spaced at 0.0191m along a radial line on the simulator floor (henceforth referred to simply as surface pressures) were also measured in the experiments. The Scanivalve system used to sample the Omniprobe was also used for the pressure measurements.
description: Tornadoes are a type of severe windstorm that repeatedly have caused devastating damage to the built environment in the United States. Low-rise buildings, in particular, historically have been among the structures that are the most vulnerable to tornado damage. Failures of this type of structure are often responsible for the social and economic losses caused by tornadoes, including the loss of life and property, as well as the interruptions to many critical societal functions. The goal of this collaborative research at the University of Arkansas (UARK) and Texas Tech University (TTU) is to further advance the fundamental understanding of tornadic loading on low-rise buildings. The outcomes of this research can be used for the assessment of building performance in tornadoes, the design of new tornado-resistant buildings, and the development of retrofitting strategies to improve the performance of existing buildings in tornadoes. The research project will be integrated with educational and outreach activities at both UARK and TTU to raise public awareness of the impact of natural hazards, including tornadoes, on the built environment and society in general. At UARK, students will be involved in the research through the Freshman Engineering Program, and the George Washington Carver Research Program that provides research internships to students from Historically Black Colleges and Universities. At TTU, the project will provide research training for students in the Wind Science and Engineering Ph.D. program. The research will also be incorporated with programs such as the Severe Weather Awareness Day in Lubbock, TX, and through partnerships with local K-12 schools and national organizations, such as the 4-H Youth Development and Mentoring Program, to reach out to both local and national communities. These research, educational and outreach activities will help make U.S. communities more resilient to tornado hazards.

To achieve the research goal, this project will utilize a research approach that combines the complementary strengths of physical experiments in a tornado simulator at TTU and numerical modeling based on computational fluid dynamics (CFD) at UARK. Unlike previous experimental and numerical studies that were conducted independently, the experiments and computational modeling in this research will be systematically coordinated. Customized experiments in the tornado simulator will first serve as the basis to validate and improve the capability of the computational model in simulating near-ground tornado-like flows and in capturing the interaction between these flows and generic structural shapes. The validated computational model and additional experiments in the tornado simulator will then be used to evaluate tornado-induced forces and pressures on low-rise buildings of various envelope configurations. Tornadoes of various structures, in terms of the swirl ratios and the maximum mean tangential velocity to translation velocity ratio, will be considered. The primary outcomes of this study will be in the form of pressure and force coefficients acting on different building shapes. These coefficients, as well as the raw data and the metadata, will be archived at both UARK and TTU and made available to the natural hazards engineering community through the NSF-supported Natural Hazards Engineering Research Infrastructure Data Depot (https://www.designsafe-ci.org/).