抄録
Hot-wire anemometers (HWAs) for measuring a fluctuating velocity field can be operated in two modes, i.e., the constant current (CC) and the constant temperature (CT) modes. The CC mode suffers from a response lag due to the thermal inertia of the hot wire, whereas the CT mode can avoid this problem by virtually eliminating the inertia with a negative feedback amplifier. Thus, the HWA is almost always operated in the CT mode. The CC mode, however, is promising for many applications because of the simplicity of the electronic circuitry to heat the wire. In the present study, the response of the CC anemometer is theoretically analyzed, and a compensation scheme for the response lag is proposed. The scheme is experimentally tested in a turbulent wake flow behind a cylinder. As a result, the compensated CC mode provides results almost identical to those obtained in the CT mode, and the CC anemometer can be used as a reliable measurement technique for turbulent velocity fluctuations.
