[A-OS15] Waves, Storm Surges, and Related Hazards

[AOS15-P02] サブグリッドスケール建物情報を考慮した台風Haiyanによる高潮浸水計算

*福井 信気¹、森 信人²、金 洙列³、志村 智也²、宮下 卓也² (1.京都大学大学院工学研究科、2.京都大学防災研究所、3.熊本大学)

Storm surge is one of the coastal disasters with devastating damage and it is important to understand the inundation risk in coastal urban areas based on numerical modeling. Although numerical simulation directly considering the buildings as topography is possible, it is difficult to employ such simulation in terms of computational cost because inundation risk analyses need huge number of ensemble simulations. The authors developed the subgrid-scale model, individual drag force model (iDFM), expressing multiple building existence in a coarser computational grid cell using total sum of drag force on buildings. The hindcast of storm surge inundation targeting typhoon HAIYAN (2013) was conducted based on the 2D shallow water models and the iDFM. Furthermore, the wind drag coefficient is changed according to building submergence to consider the wind speed reduction by buildings. The sensitivity analysis of wind drag coefficient showed more than 40% smaller inundation depth and velocity near limit of inundation than when the wind speed reduction was not considered. In addition, the validation of the iDFM using the post survey results showed that the reproducibility of inundated area was improved compared to conventional roughness model.