Thesis Format
Monograph
Degree
Master of Science
Program
Mechanical and Materials Engineering
Supervisor
Tutunea-Fatan, Ovidiu-Remus
2nd Supervisor
Bordatchev, Evgueni
Co-Supervisor
Abstract
This thesis presents the results of the investigation of the performance of rectangular riblets in drag-reducing environments. It will focus on numerical simulation and experimental methodologies. The study will examine the design, fabrication and behavior of said blade riblets using both linear experimental devices and rotational experimental devices in hydro- and aero-dynamic environments. The CFD simulations will aid the validation and understanding of turbulent flow and the fluid-surface interaction with the rectangular riblets as well as the comparison to the liner experimental device that will be aided by a wind tunnel. The rotational experimental analysis will follow a similar parametric study as it will still use rectangular riblet geometry, but it will make use of Taylor-Couette flow system. The work provides a thorough understanding of flow principles and analysis of the performance of rectangular riblets, with cases in the rotational experimental apparatus of reducing drag up to 5%. The groundwork for these experiments allows future studies to evaluate and expand with the use of drag-reducing functional surfaces with focus on rectangular riblets.
Summary for Lay Audience
Surface functionality is the ability of a surface to perform a certain utility, for example a surface could be reflective or waterproof due to the texture. This work is focused on creating small textures more known as microstructures to help manipulate the flow of fluid over it. The specific microstructures studied are rectangular riblets that are long rectangular ridges along the stream direction. The importance of this work in industries such as aerospace, transport industry and automotive by potentially reducing energy use and emissions because of the change and manipulation of drag forces on said surfaces. The following thesis focuses on designing and creating an experimental set up as well as the samples with said riblets are fabricated in house. To be able to compare the experimental test results the use of simulations are done where the ideal flow is recreated. The experimental setup made with the use of a wind tunnel will be outlined in this thesis and creates a linear flow path with a force sensor that collects data. Additionally, the use of a rotational experimental device is done that uses Taylor-Couette Flow principles. This setup consists of two cylinders that rotate coaxially with the fluid in between. Finally, the results and analysis of said setups are done and it finds that there are situations where the blade riblets lead to a decrease in drag force compared to flat samples with no texture.
Recommended Citation
Oliva, Jennifer, "Investigation of Drag performance with Rectangular Riblet-Based Functional Surfaces" (2025). Electronic Thesis and Dissertation Repository. 10744.
https://ir.lib.uwo.ca/etd/10744
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