Turbulence is the major cause of friction losses in transport processes and it is responsible for a drastic drag increase in flows over bounding surfaces. While much effort is invested into developing ways to control and reduce turbulence intensities^1,2,3, so far no methods exist to altogether eliminate turbulence if velocities are sufficiently large. We demonstrate for pipe flow that appropriate distortions to the velocity profile lead to a complete collapse of turbulence and subsequently friction losses are reduced by as much as 90%. Counterintuitively, the return to laminar motion is accomplished by initially increasing turbulence intensities or by transiently amplifying wall shear. Since neither the Reynolds number nor the shear stresses decrease (the latter often increase), these measures are not indicative of turbulence collapse. Instead, an amplification mechanism^4,5 measuring the interaction between eddies and the mean shear is found to set a threshold below which turbulence is suppressed beyond recovery.

湍流是运输过程中摩擦损失的主要原因，它导致边界面上的流量急剧增加。尽管已投入大量精力来开发控制和降低湍流强度的方法^1,2,3，到目前为止，如果速度足够大，则没有办法完全消除湍流。对于管道流量，我们证明了对速度分布的适当变形会导致湍流完全崩溃，从而使摩擦损失降低多达90％。与直觉相反，通过最初增加湍流强度或通过瞬时放大壁面剪切力来实现返回层流。由于雷诺数和切应力均不会减少（后者通常会增加），因此这些措施并不表示湍流塌陷。取而代之的是，发现一种测量涡流和平均剪切力之间相互作用的放大机构^4,5可以设置一个阈值，在该阈值以下，湍流被抑制得无法恢复。