Relaxation Behavior of a Hot-Film Anemometer under Imposed Bias Flow.

摘要

The response of a hot-film anemometer to vertical hydroacoustic particle motion is influenced by free convection, which acts as a bias flow. At this low flow speed the output is proportional to particle displacement for a wide range of parameters. While investigating the response of the anemometer to hydroacoustic motion under an imposed bias flow, it was found that a relaxation-type transition takes place from dependence on particle speed to dependence on displacement. The relevant time constant is the residence time of the fluid particle near the sensor. This effect deserves consideration in interpretation of turbulence measurements in liquids. Keywords: Hot film anemometry; Relaxation of velocity sensors; Particle velocity; Reprints. (JHD)