海水低频声吸收与pH值的关系

DEPENDENCE OF LOW FREQUENCY SOUND ABSORPTION ON pH-VAUE IN SEA WATER

本文用共振器法测量了天然海水低频声吸收与pH值的关系。测量频率为2.91、6.82和10.76kHz;pH值范围为6.48—8.51;温度为12.6℃。测量结果与不同的声吸收公式计算值进行了比较。本文实验的主要目的之一是通过将pH值减小到足够小的数值来检验海水中MgSO_4吸收的贡献。实验结果表明:为了能用一个统一的公式较准确地预估低频和高频的海水声吸收,此公式看来应该既包括MgCO_3吸收项,又包括MgHCO_3^+吸收项。

The dependence of sound absorption in natural sea water on pH value at frequencies 2.91, 6.82 and 10.76 kHz has been measured using the resonator method. Measurements were made at 12.6℃in the pH range 6.48 to 8.51. Comparison of the experimental results with predictions based on various equations is given. One of the principal objectives in this paper is to examine the contribution of the MgSO4 absorption in sea water by reducing pH value to low enough values where the pH-dependent absorption losses become negligible. It seems clear that in order to predict sound absorption in sea water more accurately at both low and high frequency ranges with an united equation, the equation should include the MgHCO3+ absorption term as well as the MgCO8 term.