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PIARC (World Road Association), founded in 1909 and comprising 125 member governments from all over the world, is the global forum for exchange of knowledge and experience on roads, road transport policies and practices. With consultative status to the Economic and Social Council of the United Nations, the Association is contributing to a stable and sustainable global development of the road and transport sector.

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  4. Term of the Dictionary | critical flow

Term of the Road Dictionary

critical flow

  • Language : PIARC Road Dictionary / English
  • Theme : Roads Drainage and Sewerage
  • Definition : Flow conditions at which the discharge is a maximum for a given specific energy, or at which the specific energy is minimum for a given discharge [Termium Plus®]. Notes: 1. Theoretical limit between subcritical flow and supercritical flow [Egis/PIARC]. 2. Under this condition the Froude number will be equal to unity and surface disturbances will not travel upstream [Termium Plus®].