On the Problem of Sound Absorption in Air Caused by the Presence of Water Vapor

Abstract

The one-chamber method of evaluating the absorption in air caused by the presence of water vapor has been investigated, with especial attention to the variation in absorption of the wall materials of the chamber and to the methods of measurement of humidity in the range from 0–15% relative humidity. Conventional measuring techniques are discussed and the need outlined for a convenient humidity meter for the range mentioned. The absorption of the chamber walls is evaluated as a function of the humidity of the air in the chamber, using in fact nitrogen in the chamber to avoid the molecular effects arising from oxygen. A mechanism is suggested for the explanation of the quadratic dependence of the absorption in air on water vapor content.