氏名：Keita SHINADA(品田啓太)

論文題目：Study on Grasp of Flow Condition of Beach Affected by Beach Flow and Air Flow(海浜流と吹送流の影響を受ける海岸の流況把握に関する研究)

指導教員名：犬飼直之(細山田得三)　

概要(344字)：In August 2016, four young men died in Hokkaido Ishikari coast, accident occurred. On the Ishikari coast there are several other accidents caused by water accidents.
For this reason, this study aims to grasp the flow condition of the beach affected by beach flow and vortex flow and to contribute to future accident prevention measures by taking this accident as an example.
As research contents, we grasped the history of the accident at the Ishikari coast, conducted on-site survey on the coast, confirmed the fluctuation of the flow condition due to wind direction fluctuation.
 As a result of confirming the change of the sea and weather before and after the occurrence of a past event, it was confirmed that there were many cases where the wind direction fluctuation occurred. From this, it is considered that the influence of the vortex flow is great in the occurrence of the accident.
Field survey confirmed the occurrence of lodging flow during climate stabilization. From this, it is considered that the flow condition of the vortex flow and the influence of the beach flow are large as the cause of the accident.
We confirmed the fluctuation of the flow due to the wind direction fluctuation from past field observation data. As a result, it turned out that the flow direction fluctuated in several hours after the wind direction fluctuated. The surface flow velocity increased after the wind direction fluctuation, so it is considered that the flow condition fluctuated greatly after the wind direction fluctuation.
The surface layer flow velocity was estimated from numerical experiments. Result The flow direction fluctuated across the Ishikari Bay a few hours after the wind direction fluctuation, and the flow velocity increased. This is qualitatively correct because it has the same fluctuation as the result obtained from observation data. From this result, it is considered that there is a high possibility that the flow velocity near the coast will increase after the wind direction fluctuation
As a future task, consider the topography condition and the equation used to estimate the surface layer flow velocity