Frequency power spectra of global quantities in magnetoconvection

TL;DR

This paper investigates the frequency power spectra of global quantities in magnetoconvection through direct numerical simulations, revealing a universal $f^{-2}$ scaling at high frequencies regardless of key parameters.

Contribution

It provides the first detailed analysis of the frequency spectra of kinetic energy, entropy, and heat flux in magnetoconvection, identifying a universal scaling law.

Findings

Power spectral densities follow an $f^{-2}$ scaling at high frequencies.

Scaling exponent is independent of Rayleigh number, Chandrasekhar's number, and Prandtl number.

Results are based on direct numerical simulations of unsteady Rayleigh-Bénard magnetoconvection.

Abstract

We present the results of direct numerical simulations of power spectral densities for kinetic energy, convective entropy and heat flux for unsteady Rayleigh-B\'{e}nard magnetoconvection in the frequency space. For larger values of frequency, the power spectral densities for all the global quantities vary with frequency $f$ as $f^{-2}$. The scaling exponent is independent of Rayleigh number, Chandrasekhar's number and thermal Prandtl number.