🔍 Scale Effects: Enhancing Wind Load Assessment on Structures

In wind engineering, the investigation of large civil engineering structures typically utilizes boundary layer wind tunnels with geometric scales ranging from 1:500 to 1:100. However, applying these conventional geometric scales to smaller, more complex structures presents two significant technical challenges: inadequate resolution of pressure data on the reduced models and the failure to accurately replicate real-world scenarios due to the models existing in the lower, highly uncertain section of the boundary layer. The WISE Research Lab is focused on developing a standardized testing protocol that rigorously accounts for both time and geometric scales to ensure accurate wind load assessment.

Systematic Examination of Scale Sensitivity

Our research involves the systematic examination of the sensitivity of wind loads on structures using a combined approach of experimental wind testing and numerical Computational Fluid Dynamics (CFD) techniques across various geometric scales.

Key Findings on Scale Impact
The comprehensive results shed light on the differential impact of model size on wind load characteristics:

  • Mean Loads: Mean wind loads remain relatively unaffected by the size of the model.
  • Peak Loads: Peak loads display significant sensitivity to the geometric scale, the spectral content of the test flow (turbulence), and the Reynolds number.

Importantly, our findings suggest that larger scales demonstrate feasibility in accurately predicting peak loads, offering crucial insights for refining wind load assessment methodologies.

Validation of Testing Protocols and CFD

We challenge existing guidelines by detailing the influence of the test building location on pressure correlation and the accurate replication of peak loads. Furthermore, we observed that the proximity of the inflow boundary plays a crucial role in accurately simulating real-world wind conditions.

CFD Large-Eddy Simulation (LES) Validation
The results obtained through high-fidelity CFD Large-Eddy Simulation (LES) align closely with corresponding pressures from open-jet facilities and full-scale data for roof component and cladding design.

  • Accuracy: The CFD LES methodology showcases its prowess in generating peak pressures and loads on buildings that closely match field measurements.
  • Simulation Capability: This superior capability stems from its capacity to reproduce the spectral content of the inflow at a 1:1 full scale.

Enhancing Design Guidelines

This research signifies a significant step toward enhancing wind load assessment methodologies for structures. By considering the intricate interplay between time and geometric scales, we provide valuable insights that directly guide the selection of appropriate test locations and highlight the effectiveness of advanced numerical methods. These findings pave the way for improved design guidelines and code provisions. 

 

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Relevant Publications