Talks at Nordita Programs [before October 2010]
Turbulence still surprises: Explorations using a 1D model
by
→
Europe/Stockholm
FB52
FB52
Description
One computational strategy for capturing micro-scale processes not affordably resolved in multi-dimensional turbulence simulations is to represent these processes by a lower-dimensional formulation. An approach formulated in one spatial dimension, denoted One-Dimensional Turbulence (ODT), is outlined. ODT combines two 1D approaches that have individually proven successful: stochastic iterated maps and dimensional reduction of the governing equations using the boundary-layer approximation. Within ODT, sub-processes based on these two approaches are coupled so as to represent both turbulent cascade dynamics and micro-physics at dissipative scales, including their two-way interaction. ODT has predictive capability for canonical flows and has been implemented as a sub-grid closure for 3D flow simulation. (Its simpler predecessor, the Linear Eddy Model, predicts mixing in specified turbulent flow states.) The use of these models for computationally affordable exploration of otherwise inaccessible flow and mixing regimes has led to surprising insights, indicating that it can be hazardous to extrapolate empirical understanding of turbulence phenomena beyond well studied regimes.