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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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Term of the Road Dictionary

subcritical flow

  • Language : PIARC Road Dictionary / English
  • Theme : Roads Drainage and Sewerage
  • Definition : Free-surface flow in which the Froude number is less than unity and surface disturbances can travel upstream [Egis/Termium Plus®] Note: in subcritical flow, loss of head results in loss of water depth [Egis/PIARC].