DOI: 10.1615/TSFP5
MEASURED AND NUMERICALLY SIMULATED BURSTING FREQUENCY OF FLOW WITHIN AND ABOVE A SUCCESSIVELY THINNED FOREST
SINOPSIS
Intermittent coherent structures play a key role in the transport of momentum and scalars between a forest canopy and the atmosphere. Two features of coherent structures are bursts and sweeps. Transport of high speed momentum towards the canopy is defined as a sweep, wheras, transport of low speed momentum away from the canopy is defined as a burst. Capturing the time frequency of bursts is important in describing the exchange of scalars and momentum between a forest canopy and the atmosphere. We applied a single point burst detection algorithm to measured and simulated flow through a successively thinned loblolly pine canopy. Measurements were conducted in four canopies with varying leaf area density and basal area. A large-eddy simulation was used to simulate the flow within and above the two of the four canopies. Source terms were added to the momentum and sub-grid turbulent kinetic energy transport equations to represent the effect of the forest canopy. Results from a dense and an open canopy are presented. The LES under predicts the turbulent kinetic energy and time between bursts for the open canopy. This may be attributed to the sub-grid scale turbulent kinetic energy source term and the domain size.