Date of Award

Spring 2019

Project Type

Dissertation

Program or Major

Mechanical Engineering

Degree Name

Doctor of Philosophy

First Advisor

Christopher White

Second Advisor

Yves Dubief

Third Advisor

Diane Foster

Abstract

The need to reliably analyze, predict, and control the transport of mass, momentum, and energy in turbulent boundary layers is critically important across a broad spectrum of technological applications and scientific disciplines. While there has been extensive–and continuing– research investigating laboratory-scale canonical wall-bounded flows, beyond the scope of these well-studied flows there exists a broad range of application relevant flows that are far less studied. The theme of this dissertation research is to study a non canonical flow, specifically to study coupled momentum and thermal transport in pulsatile boundary layer flows.

The primary contributions of the present work are (1) the design, fabrication, and validation of a unique flow facility to study non-equilibrium boundary layer flow and (2) to use this facility to study momentum and thermal transport in pulsatile boundary layer flow over a heated wall. In pulsatile boundary layer flow, the freestream velocity has a time-steady mean component and an unsteady oscillatory component superimposed on the mean component. Pulsatile boundary layer flows are therefore periodic and unidirectional characterized by both their frequency and amplitude, and are fundamentally important in many aerodynamic, industrial, and natural flow systems.

The experimental data will be analyzed through time-average and phase-average frameworks to understand the underlying flow physics of pulsatile boundary layer dynamics. Results demonstrate a varied response between the momentum and thermal field, indicating a break down in the so called Reynolds analogy assumption. The importance of buoyant transport is also demonstrated, even at low Richardson number flows.

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