Nappe (water)

In hydraulic engineering, a nappe is a sheet or curtain of water that flows over a weir or dam. The upper and lower water surface have well-defined characteristics that are created by the crest of a dam or weir.[1] Both structures have different features that characterize how a nappe might flow through or over impervious concrete structures.[2] Hydraulic engineers distinguish these two water structures in characterizing and calculating the formation of a nappe.[3] Engineers account for the bathymetry of standing bodies (like lakes) or moving bodies of water (like rivers or streams). An appropriate crest is built for the dam or weir so that dam failure is not caused by nappe vibration[4] or air cavitation from free-overall structures.[5]

  1. ^ "Water and Wastewater Terms". Sacramento State (Office of Water Programs). Retrieved 21 April 2018.
  2. ^ "What is the difference between a dam, a weir and a barrage?". GreenBug Energy Inc. Retrieved 21 April 2018.
  3. ^ Chanson, Hurbert (1 January 1994). "Hydraulics of Nappe Flow Regime above Stepped Chutes and Spillways" (PDF). CE36 (1): 69–76. Retrieved 21 April 2018. {{cite journal}}: Cite journal requires |journal= (help)
  4. ^ Lodomez, Maurine (June 1, 2016). "Frequencies of Nappe Vibration for Free-overfall Structures". Retrieved 21 April 2018. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ Chanson, Hurbert. "Design of Spillway Aeration Devices to prevent Cavitation Damage on Chutes and Spillways". The University of Queensland, School of Civil Engineering. Retrieved 21 April 2018.