Comparisons between various lengths of penstock and different types of waterhammer using circuit equivalent method and characteristic method are presented by digital simulation. 最后对不同类型水击和不同长度的压力钢管进行仿真，并将电路等值方法和特征线方法比较。
In this article the procedures are de-scribed for determining free-vortex segment properties.Characteristics method is used to design nozzle Milch produces free-vortex seg-ment. 本文提出了确定气动窗口所需自由旋涡气动特性的过程，讨论了特征线方法在非对称超音速喷管设计中的应用，该喷管被用来产生自由旋涡流动。
