Sweeping has no effect on renormalized turbulent viscosityetc15 Tracking Number 119 Presentation: Session: Lagrangian aspects of turbulence 4 Room: Room F Session start: 10:30 Fri 28 Aug 2015 Mahendra K. Verma mkv@iitk.ac.in Affifliation: Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India Abhishek Kumar abhkr@iitk.ac.in Affifliation: Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India Topics: - Intermittency and scaling, - Lagrangian aspects of turbulence Abstract: We perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field $\mathbf U_0$, and show that the renormalized viscosity is unaffected by $\mathbf U_0$, thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions $\langle {\mathbf u} ({\mathbf k}, t){\mathbf u}({\mathbf k}, t+\tau) \rangle$ for $\mathbf U_0 =0$ and $\mathbf U_0 \ne 0$ differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations. |