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Document Type

Thesis - University Access Only

Award Date

2014

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Stephan Gent

Abstract

This thesis investigates the use of Computational Aeroacoustics (CAA) in predicting sound generation and attenuation within a rectangular duct containing a swept helical coil. CAA is a field that has seen significant growth in recent years respective of the increase in computer resources and the advancement of commercially available computational fluid dynamic (CFD) solvers. CAA research is focused on the development of numerical simulations of acoustic sources and radiation from timedependent flow phenomena. Generally, these numerical simulations are achieved by solving the full transient compressible Navier-Stokes equations. In this investigation, the commercially available CFD software Star-CCM+ from CD-Adapco is used for predicting fluid mechanical effects and sound generation. A duct and coil geometry are created in CAD software and then imported to the CFD solver. The computational mesh is generated through a series of refinements aided with use of broadband noise source models which implement acoustic analogies. These models predict locations and strengths of acoustic sources by solving for surface and volume sound values regarding fluid-surface interaction and turbulent flow. Mesh refinement is performed using steady-state Reynolds averaged Navier-Stokes (RANS) equations with a two-equation turbulence closure model to reduce computational costs. Following completion of a refined mesh, a transient simulation is implemented using a hybrid method of RANS and spatially filtered Navier-Stokes equations. Point sources are defined within the fluid domain to perform Fast Fourier transforms (FFT) to acquire Sound Pressure Level (SPL) versus frequency data for comparison with experimental microphone data at a future time.

Library of Congress Subject Headings

Aeroacoustics
Heating Ventilation

Description

Includes bibliographical references (pages 132-135)

Format

application/pdf

Number of Pages

152

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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