THE VARIATION OF LOCAL SCOUR PATTERN AROUND REPRESENTATIVE NATURAL VEGETATION ELEMENTS


Yağcı O., Kitsikoudis V., Çelik M. F. , Hodoglu C., Kırca V. Ş. Ö. , Valyrakis M., ...More

36th IAHR World Congress, Delft, Netherlands, 28 June - 03 July 2015, pp.3088-3096 identifier

  • Publication Type: Conference Paper / Full Text
  • City: Delft
  • Country: Netherlands
  • Page Numbers: pp.3088-3096
  • Keywords: Flow-vegetation interaction, vegetation induced scour, scour-hole geometry, DOPPLER-VELOCIMETER DATA, FLOW, BIOMECHANICS, TURBULENCE, DRAG
  • Istanbul Technical University Affiliated: Yes

Abstract

The flow-vegetation interaction is a complicated process, which is further exacerbated when it is studied on movable bed resembling natural conditions. Nonetheless, developed scour patterns around instream vegetation are able to provide useful information with regard to the physical processes and natural mechanisms occurring during such interactions. The present experimental work investigates the scour patterns generated around several utilized obstacles to the flow and examines the generated flow field in the vicinity of the scoured flume bed. The utilized obstacles are an emergent rigid cylinder, an emergent array of smaller cylinders arranged in a circle with a diameter equal to that of rigid cylinder, an emergent natural plant, and a submerged natural plant. All of these cases are studied for the similar discharge and each case provided a distinct scour pattern, associated with the characteristics of the respective element. Subsequently, in equilibrium conditions the bottom was scanned by a high resolution laser scanner. After the equilibrium conditions had been attained the instantaneous flow velocity close to the bottom was measured three-dimensionally by means of a Vectrino II acoustic Doppler profiler and the developed flow pattern is presented in terms of streamwise mean flow velocity and turbulence kinetic energy profiles.