Hurricane storms such as Sandy and Typhoon Haiyan in the Philippines have caused catastrophic damage. In the near-coast region, a large amount of this damage has been from wave and surge impacting buildings and other structures. Currently there are criteria for surge and wave loads that are used for design. However, standard empirical loads neglect the effects of unsteady wave and surge processes, which can lead to much larger loads in the immediate vicinity of the shoreline. This project will pursue fundamental research into the nature of these unsteady structural loads, and how they affect buildings. Computational simulation backed up by case studies from Hurricane Sandy and Super Typhoon Haiyan in Philippines will develop and test representations for near-coast structural loading from unsteady waves and surge. Results will allow engineers and planners for better designs as they work to reduce damages from future hurricanes.
The neglect of unsteady radiation stresses in standard phase-averaged wave and surge models results in underestimation of maximum wave heights and current velocities in the near-coast region, and the neglect of bore-like loading. This can lead to severe underestimates of structural design loads. The research team will examine these processes using Boussinesq and Navier-Stokes fluid mechanics models to (1) map regions where low-frequency hydrodynamic processes are significant; (2) establish relationships between hydrodynamic properties and associated structural loading for canonical geometries; and (3) synthesize these results for design purposes. Loads will be subdivided into impact and quasi-steady categories, with different analyses and synthesis for each. The hypothesis that specific momentum flux is proportional to loading will be tested closely, as this may provide a relatively simple method to incorporate many of these processes into structural loading parameterizations.
