B Ghorbani - Water Engineering Department, College of Agriculture, Shahr-e-Kord University
A Karimi - Soil Science Department, College of Agriculture, Shahr-e-Kord University

The principal purpose of this research was to study the effect of single and double submerged vanes as countermeasure techniques for local scour at a cylindrical pier. For this purpose, several heights of vane ,angles of orientation, and flow depths were evaluated, all for a constant Froude Number condition (i.e., 0.15). It was found that not all types of single isolated submerged vanes can be used as a scour countermeasure at a cylindrical pier. The highest reduction in scour depth (i.e., 17.3%) was achieved for an angle of 8.5° and a flow depth of 20 cm for a vane height equal to 0 cm and the most exacerbated case occurred for a vane angle of 18.5° and a flow depth of 10 cm for a vane height equal to 5.7 cm. So, as a concluding note for vane heights other than 0 cm studied here, it may be said that there was progressively greater increase in scour depth at the cylindrical pier compared to the control. For two vane attached to the pier, a reduction of 87.7% in scour depth next to the pier was achieved for a constant flow depth (i.e., 15 cm), a constant vane angle (i.e., 18.5) and at 0 distance upstream from the pier for a vane height of 0 cm.

Cylindrical pier, double vanes, scour, single vane