On the Amplification of Density Waves in Long Pipelines Connected with a Dredge

摘要

During dredging operations the density of mixture transported along the pipeline of" a conveying system varies in time and space. The density waves generated at the inlet of the system tend to transform their shape while moving along a pipeline. Under suitable conditions (a partially-stratified flow, low mean velocity of the mixture) high density waves tend to be amplified. This process is associated with the hydrodynamic interaction between the granular bed at the bottom of a pipeline and the suspension stream above the bed. The strongest amplification of high density waves occurs at mixture velocities around or below the deposition limit value. On the basis of the field measurements the paper quantifies the development of density waves and discusses the mechanisms leading to the deformation of density waves along a long pipeline.