Wind Loading on a Generic High-rise Building
by Lup Wai Chew
Motivation and Objective
This project was supported by the SimCenter, which is developing the Wind Engineering – Uncertainty Quantification (WE-UQ) tool, aimed at supporting uncertainty quantification research for wind engineering. Current capabilities include quantifying uncertainties in structural parameters (e.g., damping) that will affect the structural response to a specific wind pressure load, but there is no mechanism to account for uncertainty in the wind pressures loads themselves. Large eddy simulations (LES) are a promising tool for accurate evaluation of these wind pressure loads, but one of the main challenges is to prescribe representative inflow turbulence in the simulations. This project leveraged the SimCenter turbulence inflow tool to evaluate the importance of uncertainties in the inflow boundary conditions for LES predictions of wind loading on a high-rise building. A wind tunnel dataset for validation is available from the TPU database.
Methods and Results
The SimCenter Turbulence Inflow Tool (TInF) is used for inflow turbulence generation. There are four methods for turbulence generation in TInF; for this study we adopt the digital filter method (DFM). The input parameters needed in the TInF DFM code are the mean velocity, Reynolds stress tensor, and turbulence length scales, which are prescribed as vertical profiles at the inlet of the computational domain. Since we are using the experimental data from the Aerodynamic Database of High-rise Buildings available from Tokyo Polytechnic University for validation, the TInF input parameters should be derived to match the wind conditions in the wind tunnel. However, the TPU database only provides the mean velocity and streamwise Reynolds stress component.
Since the database does not provide the vertical, spanwise, and shear components of the Reynolds stress tensor or the length scales, these inputs are estimated based on similarity relationships for a neutral surface layer. Furthermore the sensitivity of the simulation outputs to these uncertain inputs is assessed by running simulations with a range of values for the turbulence intensities and length scales. The figure below shows an example result, indicating the sensitivity to the vertical and spanwise Reynolds stresses.
We are currently compiling all results in a database that will be accessible through the SimCenter WE-UQ tool to support assessing the effect of the uncertainty in the wind pressure loads on the overall structural response of the building.
Acknowledgements and Resources
This research is funded by Award Number 1612843, Natural Hazards Engineering Research Infrastructure: Computational Modeling and Simulation Center (SimCenter).