Mechanical Engineering & Applied Mechanics

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Research from the Department of Mechanical Engineering & Applied Mechanics. The department website may be found at https://www.ndsu.edu/me/

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Browsing Mechanical Engineering & Applied Mechanics by Subject "airfoil"

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    Dynamic Stall Characteristics of a Pitching Swept Finite Aspect Ratio Wing
    (North Dakota State University, 2019) Tomek, Kristopher
    This research will investigate various swept wing models, designing the mechanism for their pitching motion and control, designing wind tunnel implementation, and performing data measurements and analysis using particle image velocimetry. A NACA0012 section with an aspect ratio of AR = 4, free stream velocity of U∞=34 m/s, and Reynolds Number is Rec=2x105. Swept airfoils of Λ=0°, 15°, and 30° will be pitched sinusoidally between an AoA of 4°and 22°, at a reduced frequency of k=πfc/U∞=0.2. Higher sweep angles developing arch-type vortices interact with wing tip flow and abrupt tip stall is observed. Lower sweep angles possessed defined leading edge vortices persist near the tip after lift has collapsed at mid span. Stall angle was delayed during dynamic motion of the wing as well as the presence of arch and ring type vortices increased with sweep angle and contributed to flow reattachment along the top surface of the wing.
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    Generation and Analysis of Streamwise Vortices from Vortex Tube Apparatus
    (North Dakota State University, 2020) Carlson, Bailey McKay
    A pressurized vortex tube is used to generate streamwise vortices in a wind tunnel and the resulting flow behavior is analyzed. The apparatus is intended to verify computational data from the AFRL by offering a method of conducting real-world counterpart experiments. The apparatus design process and other considered approaches are discussed. The vortex tube is operated at pressures of 20, 30 and 40 psi while the wind tunnel is operated at 3, 5, 10 and 20% capacity. Flow measurements are performed using particle image velocimetry to observe vortices and freestream interactions from which velocity and vorticity data is comparatively analyzed. Results indicate that vortex velocity greater than freestream flow velocity is a primary factor in maintaining vortex structures further downstream, while increased supply pressure and reduced freestream velocity also reduce vortex dissipation rate. A brief analysis of the vortex interaction with a downstream airfoil is presented to support future work.