Experiments in Fluids

, Volume 37, Issue 2, pp 219–229

Turbulent drag reduction in dam-break flows

Authors

    • von Kármán Laboratory for Environmental FlowsEötvös University
  • Dominique Jan
    • von Kármán Laboratory for Environmental FlowsEötvös University
  • K. Gábor Szabó
    • HAS Research Group, Institute for Theoretical PhysicsEötvös University
  • Tamás Tél
    • von Kármán Laboratory for Environmental FlowsEötvös University
Original

DOI: 10.1007/s00348-004-0804-4

Cite this article as:
M. Jánosi, I., Jan, D., Szabó, K.G. et al. Exp Fluids (2004) 37: 219. doi:10.1007/s00348-004-0804-4

Abstract

The role of turbulence is investigated in dam-break flows, where a finite volume of fluid is released from a compartment into a long, rectangular channel. After a sudden removal of the lock gate, a gravity current, undular bore, or solitary wave develops, depending on the ambient fluid height in the channel. The temporal evolution of the moving front has been measured and evaluated. It was observed that the dilution using a very small amount (a few weight ppm) of a long chain polymer (polyethylene-oxide) in the fluid strongly affected flow properties. Pronounced drag reduction has been found in dry bed flows (whereas the polymer increased the viscosity of the fluid). The presence of a few mm-thick ambient fluid layer in the channel effectively destroyed drag reduction, in spite of the fact that strong turbulence was obvious and the propagation velocity of the front was almost unchanged.

Copyright information

© Springer-Verlag 2004