基于分子弹性碰撞的大气声波衰减模型  

A Reduced Model for the Attenuation of Sound due to Molecular Collisions

作　　者：李兵 吴德金[2] 

机构地区：[1]湖南省安化县气象局,湖南益阳413500 [2]中国科学院紫金山天文台,江苏南京210008

出　　处：《河北师范大学学报（自然科学版）》2014年第4期367-371,共5页Journal of Hebei Normal University：Natural Science

基　　金：国家自然科学基金(10973043)

摘　　要：提出了一组考虑分子弹性碰撞的干空气-水汽双流体方程,利用该方程研究了水汽对大气声波衰减的影响.结果表明,当声波频率远低于弹性碰撞频率时衰减系数对水汽含量不敏感,越靠近弹性碰撞频率水汽含量的影响越明显;对于某一频率的声波衰减系数随混合比增加而增加.声波频率与分子弹性碰撞频率比是衡量弹性碰撞过程对声波衰减影响的重要参数,大气中氧分子-氮分子的弹性碰撞频率高达109 Hz,其对可闻声衰减的影响可以忽略.研究结果有助于进一步理解分子碰撞过程对大气声波衰减的影响.Based on a reduced two-fluid model for dry air and water vapor,the effect of water vapor on the attenuation of sound is studied.The results show that for waves with frequencies much less than the elastic collisional frequency between dry air molecule and water vapor molecule,the attenuation coefficient is insensitive to the mixing ratio.When the wave frequency becomes comparable or greater than the elastic collisional frequency,the attenuation due to water vapor becomes very strong.The result may help to understand the effects of molecular processes on the attenuation of sound.

关 键 词：双流体方程 大气声波 弹性碰撞 衰减 

分 类 号：P407.3[天文地球—大气科学及气象学]