Mapping Pressure Fields and Failure Mechanisms

The interaction between a tornado's complex wind field and a structure is a classic aerodynamic problem. In the controlled environment of our vortex simulator, we use detailed scale models of buildings—from simple rectangular boxes to complex multi-story designs—instrumented with hundreds of pressure taps. As the simulated tornado vortex translates over the model, we map the dynamic pressure field across every surface. This reveals the critical areas of peak suction (often at roof corners and eaves) and the rapid pressure fluctuations that can cause fatigue failure. We study not just the steady-state forces, but the transient loads as the vortex core passes directly overhead, an event that can cause the exterior walls to experience extreme outward pressure while the roof is being sucked upward.

Urban Canyon Effects and Community-Scale Aerodynamics

Moving beyond single structures, we create scaled models of neighborhoods and urban centers to study the "urban canyon" effect in tornadoes. How do buildings channel, accelerate, or disrupt the flow? Our research shows that the arrangement of buildings can create localized wind speed-up zones, potentially making certain streets or alleys more dangerous than open fields. We also study how debris is transported and trapped within these built environments. This community-scale aerodynamics research is vital for urban planners and developers. It can inform guidelines on building spacing, orientation, and the placement of critical facilities like schools and hospitals to minimize collective risk. For existing communities, it can identify areas where retrofitting or windbreaks (like berms or dense tree lines) might be most beneficial.

The data from these scale model tests is used to validate and improve computational fluid dynamics (CFD) software used by architects and engineers worldwide. By providing a rich, high-fidelity dataset of pressures and forces under a known vortex flow, we enable software developers to ensure their digital tools accurately predict real-world behavior. We also work directly with the building code committees, providing the empirical evidence needed to update design wind load provisions for tornado-prone regions. Historically, codes have been based on straight-line hurricane winds; our work is helping to define the distinct, swirling load cases imposed by a tornado, leading to recommendations for stronger connections and more robust cladding systems.

• Design and Fabrication of Instrumented Architectural Scale Models
• Pressure Coefficient Databases for Common Residential and Commercial Building Forms
• Analysis of Wind Loading on Non-Building Structures: Billboards, Transmission Towers, Storage Tanks
• The Effect of Building Porosity (Openings) on Internal Pressurization and Failure
• Studies of Aerodynamic Mitigation Features like Parapets and Rounded Corners
• Validation of Commercial CFD Software Packages Against Wind Tunnel Data
• Development of Simplified Design Guidelines for Tornado-Resistant Construction

This aerodynamic research embodies the institute's translational mission. It takes the fundamental physics of a tornado vortex and applies it to the concrete problem of keeping people safe inside their homes and workplaces. Every pressure trace, every video of a model's failure sequence, contributes to a knowledge base that empowers engineers to design structures that can stand firm against the vortex's might. In doing so, we help transform the built environment from a collection of vulnerabilities into a network of shelters.