We came up with an idea to use images and movies uploaded to the Internet by the general pubric. Dergarabedian investigated the relationship between the maximum wind speed of tornadoes and shape of funnel clouds using a two-dimensional Rankine vortex in 1970 . However, real tornadic vortices have three-dimensional structures. Therefore, the relationship between characteristics of tornadoes and their funnel clouds should be investigated considering three-dimensional tornadic flows.
In this study, three dimensional real-scale tornado-like vortices were produced using Large Eddy Simulation in OpenFOAM with very simple numerical grid and boundary conditions as shown in Figure 1 . Moreover, funnel clouds for these flows were calculated assuming that only temperature change is adiabatic. In this manner, the relationships between characteristics of flows and shapes of their funnel clouds were investigated. Figure 2 shows an example of the simulated funnel clouds. Furthermore, debris clouds for these flows were obtained through three-dimensional motion simulation of debris. Figure 3 shows a snapshot of the simulated funnel and debris clouds.
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