If the traffic density increases much above that, the flow pattern begins to become unstable.

如果车辆密度大幅高于上述数字，则车流模式开始出现不稳定现象。

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To investigate the roles of centrifugal instability on the linear growth rate of the flows, the azimuthal velocity of the basic flow is either centrifugally stable or unstable.

为了研究离心不稳定对线性增长率的影响，本研究中基本流的周向速度可以是离心稳定的，也可以是离心不稳定的。

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In the unstable flow the radial distribution of tracer gas concentration is asymmetry.

在不稳定的流动状态下，气体的径向浓度分布曲线两边出现不对称。

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When the number of cars on the road is greater than that, the flow becomes unstable and natural fluctuations in our driving style alone are enough to cause traffic.

FORBES: How To Solve Traffic

The water, albeit in smaller volumes, continues to flow, forming unstable layers of snow, slush and ice (see 2:08 when Gadd sinks his hooks into a piece of snow that simply crumbles away).

BBC: Daredevil duo is the first to scale Niagara Falls

Of course when the dollar is weak and unstable, a disharmony reveals itself among the productive that frequently retards what should be the peaceful flow of goods.

FORBES: Memo to Washington: Economic Growth Is Easy