This is a project about fundamental and applied problems in turbulent flows under different symmetry breaking mechanisms, concerning both Eulerian and Lagrangian statistics. We propose to perform a series of state-of-the-art Direct Numerical Simulations of homogeneous turbulence under mirror symmetry breaking (with direct input of helicity) and with different rotation rates. In such a set-up we expect the presence of a split-cascade regime: energy goes to large scales, helicity to small scales. In order to disentangle such huge bi-directional range of scales it is mandatory to achieve a world-record spatial resolution. Moreover, we propose for the first time for this set-up to combine Eulerian and Lagrangian measurements by seeding the fluid with millions of tracers and inertial particles, in order to study both single and multi-particle statistics in presence of direct helicity and inverse energy cascade for different values of the control parameters, the Reynolds number, the Rossby number and with different mirror-symmetry breaking mechanisms. The project aims to ask fundamental questions concerning all flows under rotation, about the interactions between slow (large-scale) tornado-like structures and the sea of small-scales tangled filaments, about the isotropic and anisotropic components of the Eulerian statistics and about relative dispersions for both fluid particles and inertial particles. Only a Tier-0 machines offer the computational resources for such challenging resolution and challenging physical set-up.
NewTURB - Effect of Helicity and Rotation in Turbulent flows: Eulerian and Lagrangian statistics
2014
Abstract
This is a project about fundamental and applied problems in turbulent flows under different symmetry breaking mechanisms, concerning both Eulerian and Lagrangian statistics. We propose to perform a series of state-of-the-art Direct Numerical Simulations of homogeneous turbulence under mirror symmetry breaking (with direct input of helicity) and with different rotation rates. In such a set-up we expect the presence of a split-cascade regime: energy goes to large scales, helicity to small scales. In order to disentangle such huge bi-directional range of scales it is mandatory to achieve a world-record spatial resolution. Moreover, we propose for the first time for this set-up to combine Eulerian and Lagrangian measurements by seeding the fluid with millions of tracers and inertial particles, in order to study both single and multi-particle statistics in presence of direct helicity and inverse energy cascade for different values of the control parameters, the Reynolds number, the Rossby number and with different mirror-symmetry breaking mechanisms. The project aims to ask fundamental questions concerning all flows under rotation, about the interactions between slow (large-scale) tornado-like structures and the sea of small-scales tangled filaments, about the isotropic and anisotropic components of the Eulerian statistics and about relative dispersions for both fluid particles and inertial particles. Only a Tier-0 machines offer the computational resources for such challenging resolution and challenging physical set-up.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.