Date of Award

12-2023

Degree Name

MS in Aerospace Engineering

Department/Program

Aerospace Engineering

College

College of Engineering

Advisor

Nandeesh Hiremath

Advisor Department

Aerospace Engineering

Advisor College

College of Engineering

Abstract

Obtaining aerodynamic forces and moments about all three orthogonal axes for arbitrary shapes at arbitrary orientations in a fast manner via a measurement technique specific to Cal Poly’s low-speed wind tunnel to continually obtain the forces and moments under quasi-steady conditions is explored. A Continuous Rotation Technique (CR) uses a 6-DOF load cell and stepper motor to rotate an object about an axis for a complete rotation. The forces and moments acting upon the object pass through the stepper motor and interface plates and recorded by the load cell as the object is rotated continuously a finite number of rotations. An optical encoder installation tracks the progress of a rotation serving indicator between the subsequent rotations to determine starting angles and body slippage. Average loading of measurements at each timestep along the average time for rotation is found. This dataset along the average time is placed in 1-degree bins and averaged to a final dataset of load measurements at 0.5-degree intervals for a complete 360-degree load map. Testing of this technique is performed on aspect ratio 1 circular cylinder and for a sphere. These test cases are representative of the 3D flow features that are prevalent for bodies of finite aspect ratios. The airloads on these canonical shapes were used to calibrate the measurement technique deriving similarity with prior work performed at Georgia Tech's wind tunnel. This thesis showcases the repeatability of the results in a different and smaller wind tunnel with improved certainty on angle measurements. The scope of the thesis tackles the showcase of an initial proof of concept for the incorporation of such a novel measurement technique using Cal Poly resources.

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