Date of Award

6-2022

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Mechanical Engineering

First Advisor

Ali Hamed

Keywords

PIV, fluid mechanics, roughness

Abstract

Volumetric particle image velocimetry (PIV) was used to experimentally study the effects of localized blowing on the turbulent boundary layer over two-dimensional k-type roughness. The experiments were performed at a Reynolds number of 100,000, based on the boundary layer thickness and the freestream velocity. Flow measurements were performed at a channel flow rate of 1 m/s for 5 cases, including a baseline no-injection case. The additional four cases included localized blowing through five small spanwise jets considered at two rates and two injection locations. Flow organization was found to be maintained across all five cases due to the relatively low volumetric flow rate of the jets: below 0.12% of the overall flow rate. Localized blowing was found to alter the time-averaged streamwise velocity, boundary layer characteristics, Reynolds shear stress, turbulent kinetic energy, and flow vortical structures. Volumetric measurements were able to capture spanwise variations of up to 18% in reattachment length and other spanwise variations in the flow quantities listed above. The volumetric measurements also enabled the visualization of flow coherent structures, including the counter-rotating vortex pair occurring between each adjacent jet.

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Rights Statement

In Copyright - Educational Use Permitted.