中文摘要：

内燃机缸内湍流场在内燃机的工作过程中扮演着极为重要的角色,对该特殊流场的分析除了需要精确的记录还需要科学的数学分析方法.该研究作为一种尝试,应用动态模态分解方法（DMD）对内燃机缸内流场采用粒子图像测速（PIV）测量数据库进行加工,研究缸内流场在不同频率下的流动特性,包括不同频率下涡团结构形态及其空间分布、能量/强度的分布及其耗散情况,从而有利于丰富人们对内燃机缸内湍流场特性的认识.

英文摘要：

In-cylinder flow field plays a key role in the internal combustion engine working process. Besides the accu- rate flow data recording, reasonable mathematic processing method is also important. The dynamic mode decomposition（DMD） was used to analyse the in-cylinder flow field PIV dataset of an optical spark ignition direct injection （SIDI） engine. The turbulence characteristics under different frequency were studied, including the vortices structure spatial distribution, flow energy/intensity distribution and decay rate. The study enriches the understanding of the in-cylinder flow field.