Abstract
The Nankai Trough Earthquake Tsunami is predicted to occur in the near future in Japan. One of the countermeasures to be taken against the tsunami attack is to predict how long salt water carried by a river-runup tsunami would stay in the river to prevent a water purification plant from taking in salt water.
In this study, an application of a hybrid 2DH-3D model to salt water behavior caused by a river-runup tsunami was conducted. The hybrid model is useful for coupling of tsunami propagation from the wave source in 2DH to the flow in the estuary area in 3D, where the density current should be considerable. Two conditions of river flow rate were considered to analyze the effects on the vertically-distributed salinity transport. It was shown that although free surfaces were similar between 2DH and 3D models, significant vertical distributions of the density were present in the 3D region, indicating applicability of the hybrid model to the situation.
