Makoto Takao

VISUALIZATION OF FLOW PATTERN OF TSUNAMI IN A HARBOR

Tsunami causes extreme erosion and accretion in the bottom of a harbor.The collision force of the floating objects is also one of the problems in tsunamis disaster.To understand them, hydraulic model experiments are carried out.Flow pattern in a harbor by tsunami are measured by PTV (Particle Tracking Velocimetry), one of the flow visualization methods.Tsunami intrudes in the harbor along the breakwater, and generates a circulation inside.In case of tsunami that has a large wave gradient, the super-critical flow and hydraulic jumps can be seen in the mouth of a harbor.Accuracy of PTV was also verified in the experiment.The velocity by PTV is compared with that by an electromagnetic current meter.Those have quite good agreements except the space where the hydraulic jump exists.