Abstract
The fluid forces acting on a cylindrical structure in inundation flow were measured by using a multi component load cell. The time variation of typical principal velocity and water depth of coming inundation flow were also measured exactly by using laser doppler anemometer and wave gage. The drag coefficient of cylindrical structure in inundation flow decreases with increase of instantaneous fluid number of coming inundation flow. This phenomenon is quite similar to the relationship between the drag coefficient and fluid number of cylindrical structure in uniform flow in open channel.
