Flow instability in high‐Prandtl‐number thermocapillary liquid bridges exposed to a coaxial ambient gas stream

Abstract

AbstractNumerical studies have been conducted in order to investigate the linear stability of thermocapillary flow in a liquid bridge suspended between two coaxial, solid rods of different temperatures. We address the full two‐phase flow problem in which both the rods and the liquid bridge are placed in a concentric cylinder and exposed to a nominally axial flow field. Two features distinguish our linear stability analysis from earlier investigations. Firstly, our computational model allows the liquid–gas interface of the basic flow to be dynamically deformable, being affected by the basic temperature and velocity fields. Beyond that, our model accounts for the full temperature dependence of all thermophysical properties of the fluids. Since the problem involves many parameters, we consider a liquid bridge of 5 cSt silicone oil (Pr = 68) and focus on the effect of the ambient gas (Argon) on the flow instability that leads to the onset of three‐dimensional flow. Critical modes are analyzed for a length‐to‐radius aspect ratio of Γ = 1.