Abstract
In order to detect acoustic waves in the flows without disturbing them, a new type of microphone called coiled optical fiber microphone is proposed. It is found that the frequency shift of lights through curved optical paths is proportional to the acoustic pressure amplitudes. Based on the principle of the frequency shift, therefore, acoustic measurements in flows become possible, provided that the noises from solids can be properly isolated. The new optical fiber microphone was embedded on the surface of an airfoil and its performance test was done in a wind tunnel. Results are reported in this paper.
