Free surface deformation of a test fluid induced by steady and oscilla
tory thermocapillary flow in a small cylindrical container (diameter =
4.8 mm) is studied experimentally. The fluid (2 Cs oil) is heated by
a cylindrical wire (diameter = 0.48 mm) placed along the centerline of
the cylinder. The relative displacement and oscillation frequency of
free surface are measured in a radial cross-section for various applie
d temperature differences. It is found that the amplitude of the free
surface height oscillations is large near the heater and the cold wall
and relatively small in the middle part. The frequency of the free su
rface oscillations is same as the frequency of the temperature oscilla
tions. Based on these data, the free surface motion during oscillation
s is delineated.