Correlation between Energy and Temperature Dissipation Rates in Turbulent Flows

Abstract

The correlation coefficient ρ between the locally averaged energy and temperature dissipation rates, ∈ and ∈ θ respectively, is studied using measurements in a plane wake, decaying grid turbulence and a round jet. In the first two flows, ∈ and ∈ θ are approximated by quantities, denoted by ∈ ap and ∈ θap respectively, derived from measurements using a probe comprising a combination of 4 hot wires and 2 cold wires. In contrast to the wake, the magnitude of ρ in grid turbulence calculated using ∈ ap and ∈ θap are comparable to those obtained using ∈ iso and ∈ θiso , the isotropic counterparts of ∈ and ∈ θ . In a particular flow, ρ decreases both with increasing wire separation and as the Taylor microscale Reynolds number R λ increases. The major effect on ρ appears to be associated with R λ although a possible dependence of ρ on the flow type cannot be discounted.