Turbulent mixing and entrainment in a gravity current
- Los Alamos National Laboratory
- ENS-LYON, FRANCE
- PURDUE UNIV.
We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model: the turbulent vertical fluxes of momentum and buoyancy are found to scale quadratically with the vertical mean gradients of velocity and density. The scaling coefficient is the square of the mixing lenth, approximately constant over the mixing zone of the stratified shear layer. We show how, in different flow configurations, this length can be related to the shear length of the flow ({var_epsilon}/{partial_derivative}{sub z}u{sup 3}){sup 1/2}. We also study the fluctuations of the momentum and density turbulent fluxes, showing how they relate to the mixing phenomena, and to the entrainment/detrainment balance.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1022066
- Report Number(s):
- LA-UR-10-04494; LA-UR-10-4494; TRN: US201117%%556
- Resource Relation:
- Conference: Euromech Conference: Small Scale Turbulence & Related Gradient Statistics ; October 26, 2010 ; Turin, Italy
- Country of Publication:
- United States
- Language:
- English
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