Date of Award

6-2022

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Mechanical Engineering

First Advisor

Ali Hamed

Keywords

Fluids, enviornment, canopies, PIV

Abstract

The effect of heterogeneities within submergent canopies resembling river vegetation was studied using 2D particle image velocimetry (PIV) within the 0.2 m x 0.2 m x 2 m Union College water channel. The goal of these experiments was to characterize the flow behavior prior to, within, and proceeding a local height heterogeneity. This allowed a better understanding of the flow dynamics and turbulence caused by the heterogeneities. The canopy models were made of rectangular elements within a staggered pattern; the homogenous canopy height h = 37.5 mm was used with a disturbance height hd that varied between cases. Both gap (hd/h < 1) and protrusion (hd/h > 1) cases were studied at a submergence depth H/h = 3.0. Specifically, heterogeneous cases hd/h = 0, 0.5, 1.25, 1.5, 2.0, and 3.0 were investigated and compared to the homogenous hd/h = 1 case. The results from the experiments suggest that, macroscopically, the gaps minimally affect the shear layer that has previously developed over the homogenous canopy. However, local height heterogeneities in the form of protrusions result in a separate shear layer formation past the heterogeneous section. The larger the protrusion, the stronger and more spatially compact the new shear layer is, therefore taking longer to dissipate and reconnect with the homogeneous shear layer.

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Rights Statement

In Copyright - Educational Use Permitted.