This is called a rarefaction and is represented by widely spaced dots.
这个区域称为稀疏区,并用疏散的小点表示.
辞典例句
The classical elementary waves in Riemann solutions include rarefaction wave, shock wave and contact discontinuity.
黎曼解涉及的经典基本波包括疏散波 、 激波和接触间断.
互联网
"a sound wave causes periodic rarefactions in its medium"
