A canonical model for stratified flow in estuaries and rivers

Steven William Armfield, Nicholas Williamson, Michael Kirkpatrick, Stuart Norris

Abstract


We present both fully resolved direct numerical simulation and large eddy simulation results for turbulent stratified flow in an open channel with periodic boundaries in the stream-wise direction and no-slip vertical sidewalls in the span-wise direction. A uniform heat source term is applied in the top 20% of the domain, approximating the solar heat flux into a river system. After each time step the total scalar flux input into the domain is uniformly removed allowing a fully developed flow field to be evolved and statistics collected. This approach allows fully developed stratified flow to be simulated with a density profile which includes a lower non-stratified region, steep thermocline and an upper laminar mixed layer region. The Reynolds number for the flows is in the range 5400-7300 and the bulk Richardson number in the range 0-0.4.

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Keywords


turbulent stratified flow; mixing; estuaries and rivers

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DOI: http://dx.doi.org/10.21914/anziamj.v54i0.6429



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