"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates" "uuid:b54e4876-3726-4c87-b578-e48304b334ce","http://resolver.tudelft.nl/uuid:b54e4876-3726-4c87-b578-e48304b334ce","Motion threshold of coarse particles under regular shoaling waves","Stive, M.J.F.; Terrile, E.; Reniers, A.J.H.M.; Verhagen, H.J.","","2005","Threshold of motion of coarse particles under regular shoaling waves is studied. Experiments were performed to investigate the effects of bed fluid acceleration on coarse particle stability. By varying wave height, wave period and water depth combinations of similar peak orbital velocities and weak to strong intra-wave accelerations were created. Qualitatively we found that initiation of motion occurs at or is very close to the maximum shear stress due to the combined effects of drag/lift and acceleration as introduced by Nielsen and Callaghan (2003). However, quantitatively their formulation does not lead to convincing discrimination between motion and no motion. We expect this to be due to the assumption that the coefficients for drag/lift and acceleration in their formulation are taken equal. From literature and from plotting our data against the Keulegan-Carpenter number we expect that the coefficients strongly vary caused by flow separation effects.","incipient particle motion; skewed waves; wave acceleration; KC-number; bed stability","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""