Stably stratified canopy flow in complex terrain

Stably stratified canopy flow in complex terrain

Stably stratified canopy flow in complex terrain has been considered a difficult condition for measuring net ecosystem–atmosphere exchanges of carbon, water vapor, and energy. A long-standing advection error in eddy-flux measurements is caused by stably stratified canopy flow. Such a condition with strong thermal gradient and less turbulent air is also difficult for modeling. To understand the ...

Buoyancy generated turbulence in stably stratified flow with shear

The energy evolution in buoyancy-generated turbulence subjected to shear depends on the gradient Richardson number Ri and the stratification number St, which is a ratio of the time scale of the initial buoyancy fluctuations to the time scale of the mean stratification. During an initial period, the flow state evolves as in the unsheared case. After this period, shear generates fluctuating veloc...

Coherent structures in stably stratified plane Couette flow

A large body of recent work in wall-bounded, unstratified shear flow has been dedicated to finding Exact Coherent Structures (ECS) (e.g. see the review Kawahara et al. (2012)). These are fully non-linear, invariably unstable, exact solutions which help understand how turbulence arises. The growing consensus is that the existence of these solutions is a necessary (but not sufficient) condition f...

A Numerical Study of Turbulent Stably-Stratified Plane Couette Flow

Direct numerical simulations (DNS) of stably-stratified, turbulent plane Couette flow are currently being performed on the XC-4000. The friction Reynolds number is kept approximately constant, Reτ 540 and the Richardson number Riw varies between 0 and 0.1. The flow is divided into two regions: the region close to the wall and the core region. The region close to the wall presents strong velocit...

Large eddy simulation of stably stratified open channel flow