Applicability of Taylor's hypothesis in thermally driven turbulence

Abstract

In this paper, we show that in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real space probes, a popular experimental tool. We perform numerical simulation of turbulent convection in a cube and observe that the velocity field follows Kolmogorov's spectrum ($k^{-5/3}$). We also record the velocity time series using real space probes near the lateral walls. The corresponding frequency spectrum exhibits Kolmogorov's spectrum ($f^{-5/3}$), thus validating Taylor's hypothesis with the steady LSC playing the role of a mean velocity field. The aforementioned findings based on real space probes provide valuable inputs for experimental measurements used for studying the spectrum of convective turbulence.