First Advisor

Raúl Bayoán Cal

Term of Graduation

Summer 2025

Date of Publication

9-10-2025

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Mechanical Engineering

Department

Mechanical and Materials Engineering

Language

English

Subjects

PIV, secondary flows, solar energy, surface roughness, turbulence, turbulent boundary layer

Physical Description

1 online resource (vii, 55 pages)

Abstract

This study investigates Prandtl's secondary flows of the second kind within the turbulent boundary layer over a newly defined type of surface roughness, e-type, which is characterized by roughness elements that are elevated from the wall. This e- type roughness is modeled after photovoltaic (PV) solar panels and its study driven by establishing a more robust understanding into how flow moves through solar arrays as the demand for renewable energy continues to grow.

Wind tunnel experiments using particle image velocimetry (PIV) were conducted over a scaled array of panels and explored how shifting the yaw angle of the array (angle at which the oncoming flow impacts the front of the panel) influences secondary flow structure development, size, strength, and spatial distribution. Fundamental turbulence statistics were analyzed to identify mechanisms of momentum transfer and energy transport as well as identify the generation and spatial persistence of secondary flow structures within the array and into the boundary layer. Results show that shifting yaw angle causes these secondary flow structures to grow and morph when compared to arrays that are aligned with the streamwise flow. These results indicate that yaw angle affects secondary flow structure generation, size and strength and may provide practical implications for optimizing array configuration to generate these motions within and above the array.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

https://archives.pdx.edu/ds/psu/44125

Available for download on Thursday, September 10, 2026

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