The calibration of constant temperature hot-wire anemometer probes at low velocities

This paper describes the development of calibration equations for constant temperature hot-wire anemometer probes that are valid down to velocities as low as 0.05 m/s. In this region both free and forced convection effects are relevant. Current methods of describing the interaction of the two effects are based on vectorial addition of the two convection velocities. The experimental results presented here clearly demonstrate that such methods are inappropriate. Semi-empirical equations that yield a good description of the probe behaviour in this complex region are presented. (A)