Date of Award

Fall 2019

Degree Type

Open Access Dissertation

Degree Name

Engineering and Industrial Applied Mathematics Joint PhD with California State University Long Beach, PhD

Program

Institute of Mathematical Sciences

Advisor/Supervisor/Committee Chair

Hamid Rahai

Dissertation or Thesis Committee Member

Marina Chugunova

Dissertation or Thesis Committee Member

Roger Lo

Dissertation or Thesis Committee Member

Ali Nadim

Terms of Use & License Information

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Rights Information

© 2019 Jeremy R. Bonifacio

Keywords

Annular Cavity, Jet in crossflow, Oscillatory flow, Pulse Flow, Upper respiratory system

Subject Categories

Aerodynamics and Fluid Mechanics

Abstract

Flows past a cavity are known to exhibit an oscillatory behavior with an amplitude and frequency dependent on the incoming flow properties and the geometry of the cavity. Experiments and numerical analyses have been performed to determine the effects of a flow passing through an axisymmetric cavity and discharging into a transverse freestream. The study focuses on the mechanisms involved in the generation of pulsatile flow and its influences on a jet in crossflow. Flow characteristics through the cavity and the jet in crossflow interaction were analyzed using the computational fluid dynamics software Siemens Star-CCM+. The experimental analysis utilized a Laser Doppler Velocimetry (LDV) system for measurements of velocity profiles to determine the oscillatory jet flow properties as well at the oscillation frequency. Cavity dimensions with a Length to Depth ratio of 2 was used with an incoming flow mean velocity of 50 m/s resulting in a turbulent jet with a Reynolds number of approximately 33,600. The flow through the cavity emitted an oscillatory flow at 66.68 Hz determined by a Power Spectral Density plot. The oscillatory flow in cross flow exhibited a lower jet trajectory when compared to a steady jet in crossflow and indicates increased vorticity production within the jet, supporting flow recovery immediately downstream of the jet. The passive approach of generating an oscillatory jet in crossflow can aid in mixing of the two flows. Also included in the study is an application of the cavity driven oscillatory flow as it pertains to the upper respiratory system.

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