The acoustic energy conversion efficiency of a single raindrop

Abstract

The measurement of rainfall in the ocean is more difficult than in land, but the noise signals produced by rainfall can be used for measuring the rainfall in the ocean. In this paper, a single raindrop measurement system was set up to measure the noise of the raindrop, the bubble sound is classified by the radius of the raindrop which was measured by the splash method. The mechanism of the initial impact and the bubble sound are analyzed, and the kinetic energy threshold and acoustic energy conversion efficiency of the single raindrops is also investigated. The results show that the bubble sound is the main compared with initial impact sound, the initial impact sound will become larger with the radius of raindrop, the bubble acoustic energy of large and great raindrop is much larger than that of small one, but the tiny and medium raindrop have no bubble acoustic energy. The kinetic energy threshold is not a constant, but proportional to the raindrop size. The acoustic energy conversion efficiency is about 1.04×10-3% for small raindrops, but 10-5% for heavy rain and great raindrops.