Resuspension of Sediments by Multiple Jets

Abstract

Resuspension of sediments in karstic lakes by multiple bottom-springs is mimicked using a laboratory experiment, wherein an array of axisymmetric vertical jets are forced through a planar bed of noncohesive sediments. Three different types of flow evolution are identified, namely, full deposition, where all the suspended particles settle after initial transients, continuous reentrainment, where the particles remain in individual jet cores without deposition, and particle interface, where the sediments disperse in the entire bottom layer, forming a lutocline between the turbid lower layer and clear upper layer, regimes. Because of its practical relevance, special attention is given to the particle interface regime. A semiempirical criterion for the appearance of this regime and an expression for the height of the resulting lutocline are delineated. Velocity measurements indicate that the intensity of turbulence above the lutocline is determined by the nature of particle-flow interactions in the sediment layer, characterized by the particle Reynolds number.