Date of Award

2016

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

First Advisor

Roussinova, Vesselina

Second Advisor

Balachandar, Ram

Keywords

Coherent structures, Shallow flow, Tandem cylinders, Vegetation flow, Wake flow

Rights

CC BY-NC-ND 4.0

Abstract

The present thesis deals with the vertical variability of the wake characteristics behind emergent single and tandem circular cylinders in shallow open channel flow at two Reynolds numbers (ReD = 925, 3000) in order to conceptually investigate the flow past vegetation. The tandem configuration includes two and three slender cylinders arranged in-line with different gap lengths (G) while the cylinders are rigid with a small diameter (D = 6.4 mm). The experiments were conducted in a wide water flume, where a small blockage ratio (~ 0.5%) was achievable. Velocity measurement was performed using particle image velocimetry (PIV) in vertical and horizontal planes in the wake region. The focus of the study is to explore the wake flow characteristics in terms of mean velocity profiles, turbulent parameters and coherent structures along the water depth for all test cases. Proper orthogonal decomposition (POD) was applied to educe information about the coherent structures in the flow in the different horizontal planes.

Share

COinS