Study on tsunami force mitigation of the rear house protected by the front house

The investigation of tsunami bore force mitigation is important to new houses design around already built houses. The tsunami bore is simulated by dam-break wave in the 3D numerical flume built by commercial software ANSYS Fluent, the numerical model is validated by the physical experiment. The tsunami in-line force time history of detached house without protecting barrier is divided into four stages and the characteristics of each stage are analyzed. The influencing parameters of the mitigation effect in the above four stages, including α (the relative clear distance between the front and rear houses) and β (the relative bay width of the front house), are studied elaborately. Further the mechanism of the influence of α and β are explored. Results show the tsunami in-line force on the rear house can be remarkably smaller (even become minus), or slightly larger than the case without front house when α and β changes, characteristics of the reconstruction bore behind the front house, including completeness of bore, bore height, velocity, etc. are responsible for the tsunami force changes on the rear house. At last the chart of mitigation index varies with α and β is presented.