Flow velocities and bed shear stresses in a stone cover under an oscillatory flow

F. Stenanato (Invited author), Anders Wedel Nielsen (Invited author), B. Mutlu Sumer (Invited author), Jørgen Fredsøe (Invited author)

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I order to get a better understanding of the interaction between the wave-induced, near-bed oscillatory flow, the stome cover and the sea bed, physical model tests were carried out. The tests were conducted in an oscillating water tunnel. The bottom of the tunnes was covered by one, two and three layers of stones. The flow velocities in the pores of the stones were measured using LDA (Laser Doppler Anemometer). In addition to the velocity measurements, the bed shear stresses were also measured using a hotfilm (Constant Temperature Anemometry). It is found that the boundary layer of the outer flow penetrates quite a substantial amount of thickness into the stone cover, deoending on the flow conditions above. Below this level the velocity remains constant. The level of turbulence in between the stones is found to be very high: 3 to 4 times higher than turbulence level over sipple covered bed in steady current boundary layer without any externally generated turbulence. The bd shear stress is found to be very low, more than ten times smaller than in the case of a smooth base bottom without stone cover.
Original languageEnglish
Title of host publicationICSE-5
PublisherAmerican Society of Civil Engineers
Publication date2010
Publication statusPublished - 2010
Event5th International Conference on Scour and Erosion - San Francisco, CA, United States
Duration: 7 Nov 201010 Nov 2010
Conference number: 5


Conference5th International Conference on Scour and Erosion
Country/TerritoryUnited States
CitySan Francisco, CA
Internet address


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