The effects of temperature-dependent viscosity and coefficient of thermal expansion on the stability of laminar, natural convective boundary-layer flow of a liquid along an isothermal, vertical surface are studied employing linear stability theory for Prandtl numbers 7-10. Numerical solutions indicate that the temperature-dependent viscosity stabilizes the flow along a heated wall and destabilizes it along a cooled wall. The temperature-dependent coefficient of thermal expansion initially stabilizes the flow for a heated wall but farther downstream it destabilizes the flow. Flow visualization studies in water with an isothermal, vertical copper pipe (outside diameter 41.3mm and length 1 m) for various combinations of wall and ambient temperatures in the range 5-35°C support the numerical predictions. © 1986.
Sabhapathy, P., & Cheng, K. C. (1986). The effects of temperature-dependent viscosity and coefficient of thermal expansion on the stability of laminar, natural convective flow along an isothermal, vertical surface. International Journal of Heat and Mass Transfer, 29(10), 1521–1529. https://doi.org/10.1016/0017-9310(86)90067-0