Influence of the condensate and inverse cascade on the direct cascade in wave turbulence

TL;DR

This paper investigates how the presence of a condensate and inverse cascade influence the direct cascade in wave turbulence, revealing that reducing condensate levels aligns observed spectra more closely with wave turbulence theory predictions.

Contribution

It demonstrates the impact of condensate suppression on the spectral exponents in wave turbulence and offers a qualitative explanation for this phenomenon.

Findings

Condensate presence affects the spectral exponents.

Lower condensate levels lead to spectra closer to theoretical predictions.

A qualitative mechanism explaining this effect is proposed.

Abstract

During direct numerical simulation of the isotropic turbulence of surface gravity waves in the framework of Hamiltonian equations formation of the long wave background or condensate was observed. Exponents of the direct cascade spectra at the different levels of an artificial condensate suppression show a tendency to become closer to the prediction of the wave turbulence theory at lower levels of condensate. A simple qualitative explanation of the mechanism of this phenomenon is proposed.