Effect of Pipeline Orientation on Scour Mechanism in Unidirectional Steady Flow

The 3-dimensional flow velocity components at several different points, which are distributed equally across the channel width and the associated scour hole, are measured in order to investigate the flow components and scour mechanism around fully submerged pipeline across the channel. Three different pipeline orientations, which are 30 degrees, 60 degrees and 90 degrees from the side wall of the channel are installed at fully developed flow point in the main channel. A 3-dimensional down-looking acoustic Doppler velocimeter (ADV) is then used to measure the flow velocities at several points across and along the channel. The effect of the pipeline orientation, the flow characteristics, the horseshoe vortex effect and other associated factors is discussed in the paper.