Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

A. Moutsoglou


A computational study is conducted to investigate the buoyancy effects on laminar forced flow of air in continuously or intermittently heated/cooled vertical tubes. Buoyancy assisting and buoyancy opposing flow cases are considered for heating/cooling rates that provide either uniform wall temperature or uniform heat flux conditions. An adiabatic segment separates the heating/cooling regions for the intermittently heated or cooled vertical tube. The nature of the observed effects of various heating/cooling rates and configurations on the velocity and temperature development as well as on flow reversal is explained. Critical buoyancy parameters that signal the onset of flow reversal as well as axial locations were flow reversal first occurs are determined in the study. The intermittent heating or cooling is shown to delay the velocity and temperature development but is found to have no effect on the critical buoyancy parameters that incite flow reversal.

Library of Congress Subject Headings

Heat -- Convection
Tubes -- Cooling
Fluid dynamics
Laminar flow



Number of Pages



South Dakota State University