Diagnostics of Fourier triad-phase synchronization via a phase-frozen model in 1D Burgers and 3D Navier-Stokes flows 文档正文 文档附件(0)
Nonlinear triadic interaction plays a key role in the multiscale energy transfer of turbulence.It has been observed that the Fourier triad phases are synchronised to pi/2 when energy transfer is enhanced in the 1D Burgers equation,either with the stochastic forcing (Murray and Bustamante,J.Fluid Mech.(2018))or in the developing process from specific initial conditions(Kang et al.,ar Xiv:2105.09425).The focus of this work is twofold.The first objective is to understand what triggers the phase synchronisation.We revisit the ID Burgers equation with a staircase initial condition(Fang et al.,J.Turbul.(2020))..It is found that all the triad phases are strictly synchronised to pi/2 as the energy spectrum develops.A recursive formula of triad-phase relation is proposed to demonstrate that this strict synchronisation is triggered by the convective term in the Fourier space.