FLOOTSI Development of GIS-GPU-based flood-simulation model and its application to flood-risk assessment Examples of applications Augusto Maidana, Julio García, Eugenio Oñate and Claudio Zinggerling International Center for Numerical Methods in Engineering (CIMNE) Technical University of Catalunya (UPC) Gran Capitán s/n, 08034 Barcelona, Spain maidana@cimne.upc.edu; julio@compassis.com; onate@cimne.upc.edu; czingger@cimne.upc.edu m

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast Figure 1: Initial state

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast Figure 2: Dry-out

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast Figure 3: Run-up

The Chilean tsunami event April 1, 2014 Earthquake 8.2 grados Richter in front of Iquique coast

Monai Valley: The main idea here was to test the FLOOTSI code to a real-world event, the Okushiri 1993 tsunami, for which laboratory experiments were also performed as part of the set of benchmark problems used in the 2004 Catalina Island workshop (Liu et al., 2008). The laboratory experiments of runup in the Monai Valley were conducted, aimed at reproducing and better understanding the coastal impact of the Okushiri tsunami. This experiment was modeled here as part of a validation benchmark. The laboratory model of Monai at a 1/400 scale was constructed in a 205 m-long, 6 m-deep, and 3.5 m-wide tank at Central Research Institute for Electric Power Industry (CRIEPI) in Abiko, Japan and partly shown in Fig. 1. The laboratory setup closely resembles the actual bathymetry. The incident wave from offshore, at the water depth D = 13.5 cm is known. There are reflective vertical sidewalls at X = 5.5, Y = 0 and 3.5 m (Fig. 1). The entire computational area is 5.448 m x 3.402 m, and the recommended time step and grid sizes for numerical simulations are Cell Size = 1.4 cm and dt = 0.05 sec. Figure 1 depicts the coastal topography of the complex three-dimensional beach. Figure 2 depicts the initial wave profile [ Height(m) -Time(s) ] for Monai Valley experiment.

Monai Valley: Figures 3, 4, and 5 depicts the comparison of experimental (Liu et al., 2008) and FLOOTSI’s results for wave gauges 1, 2 and 3 for the Catalina benchmark #2 of the Monai Valley. The numerical results reproduce well the salient features of the tsunami-induced flow, particularly for the lower frequency components. The time of initial wave impact and that of arrival of the reflected wave match the experimental values quite well. Figure 3 depicts the comparison between the gauge 1 (4.521 m, 1.196 m) and the numerical results of the two nearest points. Figure 4 depicts the comparison between gauge 2 (4.521 m, 1.696 m) and the numerical results of the two nearest points. Figure 5 depicts the comparison between the gauge 3 (4.521 m, 2.196 m) and the numerical results of the two nearest points.

Monai Valley: The figure 6 gives a general idea of the geometry and time evolution of the modelled tsunami. The bathymetry data and channel geometry matches that used in the experimental wave tank. The water surface is forced on the open boundary with the experimentally-imposed initial wave profile. The initial dry-out as well as extreme run-up in the narrow central valley are clearly visible in the picture, as well as wave reflections from the boundaries and dimples in the water surface caused by underwater vortices. Figure 6: depicts two stages of the time evolution of the tsunami hitting over the coast and surrounding the island. Sometimes the island is covered totally by water and produces dimples in the water surface caused by underwater vortices. [YouTube]

Monai Valley: Figure 7: the figure depicts a frame of the time evolution of the tsunami’s velocity field including the vorticity due to the presence of the island. [YouTube]