Using Lagrangian stationarisation to connect inhomogeneous turbulence in a free shear jet to idealised homogeneous isotropic turbulence
A fundamental study of a particle-laden free-shear jet is performed to investigate its non-stationary Lagrangian dynamics associated with Eulerian inhomogeneity and its consequences regarding the turbulent transport of particles. One of the difficulties to model the transport properties of such flows relies on spatial inhomogeneity, which in turn results in Lagrangian instationarity of particle dynamics. As a consequence, simple usual frameworks as the Taylor turbulent diffusion theory do not apply. Using Lagrangian Particle Tracking, statistics along particle trajectories are analyzed in order to test the relevance of Lagrangian stationarisation and self-similarity hypothesis, as originally proposed by Batchelor in 1957 to extend Taylor’s theory of turbulent diffusion to inhomogeneous flows. Inspired by this stationarisation idea, a new simple strategy to accurately model inhomogeneous jet turbulence, including subtle effects such as Lagrangiain intermittency, by « molding » homogeneous isotropic turbulence will be presented.
Contact Nathanael Machicoane for more information or to schedule a discussion with the seminar speaker.