Perpustakaan Digital ITB

This thesis discuss about improvements of the existing design of a constant temperature hotwire anemometer (CTHWA). Firstly, it will be shown that most of the noise that plagues the early prototype actually comes from a specific behaviour of the system that was related to bridge inductance widely known in the literature. Comparison of digitally filtered signals between commercial unit and the built version showed that if this behaviour can be controlled, the built CTHWA will have comparable, if not better, noise performance than the commercial unit. The primary focus of design improvements in this thesis was to have control of the system as well as the ability to test the electronics for frequency optimization. In the digital domain, computational tools were also developed to process the signal. The new system was then tested by measuring various flow including the upgraded windtunnel at the fluid diagnostic lab using a Wollaston hotwire. Comparison of the statistics of the flow measured by the built CTHWA against a commercial unit shows very promising result. Likewise, spectral analysis told similar story with the measured data having characteristics that was widely known in the turbulence literature.