Date of Award

Spring 5-2018

Access Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

John A. Ekaterinaris

First Committee Member

Anastasios S. Lyrintzis

Second Committee Member

R.R. Mankbadi

Abstract

The pressure attenuation of moving shocks when they propagate in ducts, is of great importance in a wide variety of applications, such as health, safety, and transportation. The objective of this research is to simulate the propagation of shock waves in ducts with roughness. The roughness is added in the form of grooves as in an existing experiment. Different shapes are considered in order to better understand the physics behind the evolution of the complex shock patterns resulting from diffraction, reflection and refraction of the primary moving shock. The contribution of grooves and duct shape on these phenomena and pressure attenuation is investigated. The numerical method is validated through several test cases, and the results are compared against the theory and the experimental measurements. Good agreement between high resolution computations and the experiment is obtained for the shock speeds and complex wave patterns created by the grooves. Time histories of pressure at various locations are also compared. It is found that accurate pressure history agreement requires a close representation of the full experimental setup to fully capture boundary layer development, and pressure losses associated with unsteady moving shocks in long ducts. Different groove geometries have been tested in the numerical computation in order to identify the shape that will diminish shock strength, hence pressure extrema more effectively. Analysis and animations of the computed results are employed to reveal salient features of the unsteady flowfield.

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