手风琴效应（英文：Accordion effect）在非线性物理学中意指流通过程中，某段流动的元素所出现的不均匀涨落。这种现象可在交通、自行车比赛和管道中流动物体涨落时出现。

In physics, the accordion effect occurs when fluctuations in the motion of a travelling body causes disruptions in the flow of elements following it. This can happen in road traffic, foot marching, bicycle racing, and, in general, to processes in a pipeline. These are examples of nonlinear processes. The accordion effect generally decreases the throughput of the system in which it occurs.