Local heat transfer coefficients around a cylinder in oscillating flow

Abstract

Local and average heat transfer coefficients were determined for a right circular cylinder in an oscillating flow. Spanwise platinum heater strips were used to heat the cylinder isothermally over the lower 180 degrees from the front to rear stagnation point. The four inch diameter cylinder was positioned both normal to and at 45 degrees to the flow direction. Data was gathered for diameter Reynolds numbers from 100,000 to 300,000. Large amplitude oscillations were imposed upon the mean flow using a rotating shutter arrangement. Frequencies of 0, 5, 10, 22, 50, 100 and 126 Hertz were investigated For normal flows, local heat transfer coefficients in the wake and average Nusselt numbers were enhanced above values for steady flow, for runs having large amplitude. In the 45° flows, no significant change in heat transfer was noted with oscillating flow.