Experimental study of turbulent flow near model trashracks

Abstract

An experimental study of turbulent open channel flownear trashrack models is reported. The trashrack models comprised of an array of rectangular bars of identical thickness. The experiments were conducted for a fixed bar depth but different center-to-center spacing, and then for a fixed center-to-center spacing but different bar depths.A high resolution particle image velocimetry (PIV) technique was used to conduct detailed velocity measurements in the streamwise-spanwise planes located at mid-depth of flow. The mean velocity and Reynolds shear stress were then obtained to study the effects of bar spacing and bar depth on the velocity field and head loss. The results demonstrate that the head loss coefficient increases with increasing blockage ratio but decreases slightly when the bar depth is reduced.

Keywords:

• Blockage ratio
• experimentation
• head loss
• particle image velocimetry
• trashrack