抄録
The surface flow structure of large scale vorticies at the rear of a cylindrical pier is studied for the flow of transcritical Reynolds number is over 108. The field observation around AKASHIKAIKYOU OHASHI bridge pier was carried out. Water surface images are taken from top of the main tower using a video camera. And an image analysis method using a correlation method for the calculation of two dimensional velocity distribution of surface is examined. In the rear side of the pier, large scale vortices like Karman vortices could be seen by video and MEM spectrum of surface velocity fluctuation.
