Hydraulic resistance of submerged cylindrical elements. A two layer scaling approach

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The hydraulic resistance of vegetation can play a major role in the hydrodynamics of rivers with extensive natural floodplains. Contrary to commonly used wall roughness methods, vegetation penetrates the flow field and thereby causes drag and, subsequently, additional energy losses. In this study, these processes are treated in an idealized form by replacing vegetation with cylindrical elements with homogeneous geometrical dimensions. Based on scaling considerations of the forces involved, depth-averaged flow velocities within the roughness layer and in the free flowing layer above the roughness elements are estimated. Consequently, conditions in the two separate flow layers yield a new description of the overall average flow field, which is entirely determined by measurable geometrical boundaries. The new description shows to give good agreement with laboratory flume experiments.
Original languageUndefined
Title of host publicationNCR-days 2005. Research on river dynamics from geological to operational time scales. 3-5 November 2005, Zwijndrecht
EditorsH.J.T. Weerts, I.L Ritsema, A.G. van Os
Place of PublicationDelft
Publication statusPublished - 3 Nov 2006
EventNCR-days 2005: Research on river dynamics from geological to operational time scales - Zwijndrecht, Netherlands
Duration: 3 Nov 20054 Nov 2005

Publication series

NameNCR publication 29-2005


ConferenceNCR-days 2005


  • IR-67910
  • METIS-233966

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