Session: 10.4.1 - Vortex Dynamics I

Paper Number: 158202

158202 - Mid-Plane Stereo PIV Measurements on a Thin Circular Disk at Re 1800 

Abstract: 

Inclined disks remain understudied in the field of aerodynamics, despite their relevance to both theoretical research and practical engineering applications. While extensive research exists on thin flat plates and low aspect ratio wings, the literature concerning inclined disks is relatively scarce. Additionally, those scarce papers only examined a limited set of test criteria. Understanding the behavior of thin disks is essential for many engineering issues. These range from potential use as control surfaces and wings in autonomous underwater vehicles (AUVs) and micro aerial vehicles (MEVs) to their application in solar panels, marine structures, and other unique systems.

This study investigates the flow behavior of thin circular disks at various angles of attack in a low Reynolds number regime. The primary objectives of this work include establishing a reliable experimental setup, designing a test mount for the disk models, and processing the data gathered through Stereo Particle Image Velocimetry (SPIV) measurements in a water tunnel.

The experiments were conducted in the Cal Poly water tunnel with a SPIV system modified for safety in an undergraduate educational setting. The Cal Poly SPIV system, historically outfitted with a class 4A laser, was adapted to use class 3B lasers. While class 3B lasers are not traditionally used for SPIV, they have been shown to work well for low-speed investigations in the Cal Poly water tunnel.

The outcomes of this research aim to advance the understanding of thin disks by characterizing near-body and off-body flow structures. SPIV measurements capture time-averaged velocity fields at the disk midsection across a range of angles of attack, from zero to ninety degrees, with high angular resolution. These data sets reveal flow phenomena, including leading-edge and trailing-edge vortex formation, vortex lift forces, and shedding behaviors on both the lee and windward sides of the disk. Additionally, PIV data will be processed to capture drag coefficients, lift coefficients, and pressure acting on the disk.

The experimental setup is now fully operational, and initial data collection has been successfully completed. Preliminary results for an aspect ratio 52.5 disk at a Reynolds number of 1800 demonstrate the presence of prominent leading-edge and trailing-edge vortices. These findings highlight key aerodynamic behaviors that align with and extend prior research. This work explores a different range of Reynolds numbers and finer angles of attack than previous experimental studies. This data forms the foundation for a detailed analysis that will be included in this report. The results not only fill a critical gap in the literature but also have implications for the design of next-generation aerodynamic and hydrodynamic systems. 

Presenting Author: Travis Bouck California Polytechnic State University, San Luis Obispo

Presenting Author Biography: Travis Bouck is a dual-degree master’s student in Aerospace Engineering at California Polytechnic State University, San Luis Obispo. He plans to complete his degree in 2025. As a member of Dr. Nandeesh Hiremath’s Applied Experimental Fluids research group, Travis investigates the flow dynamics of inclined thin circular disks using Stereo Particle Image Velocimetry (SPIV). In addition to his academic research, he has gained practical experience through internships with the U.S. Air Force, U.S. Navy, and Boeing, further strengthening his background in aerospace systems and experimental methods.