Effects of time-filtering the Navier–Stokes equations

The underlying premise of temporal large eddy simulation (TLES) is that the attenuation high-frequency content also attenuates high-wavenumber content. Yet, to date, effect in wavenumber space removing oscillations by time-domain filtering not well understood. In this work, we numerically investigate relationship between frequency and with particular attention role residual-stress TLES. Moreover, since under-resolved simulations use high-order, non-dissipative numerical methods require some measure artificial dissipation for stabilization, discuss regularization term practical relevance applications Specifically, analyze effects Eulerian a causal exponential filter on homogeneous isotropic turbulence. data are generated direct Navier–Stokes equations, which driven maintain an average Reynolds number (Reλ) 200. A priori, Fourier transformations velocity fields were performed order compute unfiltered filtered energy spectra both wavenumber–frequency space. Furthermore, amount unresolved insufficiently resolved was approximated attempt estimate required additional dissipation. results indicate motivated stabilization can be reduced due filtering. it has been shown sharp cutoff domain does translate into Thus, hybrid model combines spatial might advantageous.