"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:3081b459-b67d-4406-b5e3-4a80dfcc29e9","http://resolver.tudelft.nl/uuid:3081b459-b67d-4406-b5e3-4a80dfcc29e9","Energy exchanges and time asymmetry in 3D turbulent flows","Pumir, A.; Xu, H.; Grauer, R.; Bodenschatz, E.","Pumir, A. (author); Xu, H. (author); Grauer, R. (author); Bodenschatz, E. (author)","2015","In 3D turbulent flows, the direct cascade of energy, characterized by a flux through scales, ε, is a strong source of irre- versibility. This irreversibility manifests itself in the asymmetry between negative and positive kinetic energy differences along particle trajectories. In particular, it is observed that the odd moments of the power of the forces acting on a fluid particle, p ≡ a · V are negative, and that −⟨p3 ⟩/ε3 ∝ Rλ2 . This property rests on subtle correlations between acceleration and velocity. I will discuss two representations of the acceleration a, which shed light on the irreversibility of the flow.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:424c4412-b605-4a55-bfcf-647d00d70d3d","http://resolver.tudelft.nl/uuid:424c4412-b605-4a55-bfcf-647d00d70d3d","Energy flux in isotropic turbulence under large variations of external forcing","Xu, H.; Di Lorenzo, F.; Pumir, A.; Bodenschatz, E.","Xu, H. (author); Di Lorenzo, F. (author); Pumir, A. (author); Bodenschatz, E. (author)","2015","We investigate the response of energy flux in isotropic turbulence to step-function like perturbation in external forcing at large length scales. From both physical experiments and direct numerical simulations, we measured the evolution of the Eulerian velocity structure functions, such as $D_{LL}(r)$, $D_{NN}(r)$, before and after the perturbation in forcing. In both cases, we observed the cascade of the energy excess at large scales cascade through scales to the dissipative range, which can be used to study the dynamics of the cascade, and in particular, to estimate the relevant time scales.","","en","conference paper","","","","","","","","","","","","","",""