Experimental investigation of channel flow through idealized isolated tree-like vegetation


Kitsikoudis V., Yağcı O. , Kırca V. Ş. Ö. , KELLECIOGLU D.

ENVIRONMENTAL FLUID MECHANICS, cilt.16, ss.1283-1308, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 16 Konu: 6
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1007/s10652-016-9487-7
  • Dergi Adı: ENVIRONMENTAL FLUID MECHANICS
  • Sayfa Sayıları: ss.1283-1308

Özet

Riparian and floodplain tree-like emergent vegetation alter significantly the flow field and lead to complicated three-dimensional flow patterns, characterized by increased turbulence production, with the potential to induce morphological changes. The canopy presence in tree-like vegetation leads to the formation of lee wake vortices and can induce a strong subcanopy flow. The present experimental study employs artificial, rigid, tree-like emergent vegetation elements, with relatively simple structure, in order to investigate the canopy effects on the flow field. Specifically, the tree-like canopy is simulated by placing an element on top of a wooden rod simulating the trunk. Three elements with an equal encircling diameter of 16 cm are examined as canopy in tree-like vegetation, namely a circular cylinder and two hexagonal arrays comprising smaller circular cylinders with two different individual diameters. The experiments were conducted in a 26 m long laboratory flume and the velocity measurements were carried out with an acoustic Doppler velocimeter. The results show that the canopy porosity has a direct impact on the subcanopy flow intensity and on the required distance that the flow needs to recover. In addition, the subcanopy flow disrupts the formation of a steady wake region behind the entire porous element and inhibits the development of a recognizable von Karman vortex street.