https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47182 k and 𝜀_θ, respectively, the mean dissipation rates of turbulent kinetic energy k and half the temperature variance ⟨𝜃²⟩/2, is developed for slightly heated turbulent flows of air. It is limited to a Prandtl number near unity and applicable to flows where temperature can be treated as a passive scalar. A significant advantage of the method is that 𝜀_k and 𝜀_θ can both be estimated from the measurement of a temperature frequency spectrum, G_θθ(f). The method relies on the collapse in the dissipative range of one-dimensional temperature spectra, ϕ_θ(k₁η), when normalized with 𝜀_θ, 𝜀_k, and ν. This collapse ensues from a similarity analysis of scale-by-scale budgets of the second-order structure function for the temperature. A generic spectrum 𝜙_𝜃𝐺(𝑘₁𝜂), defined in the wavenumber range 0.07 ≤ k₁η ≤ 0.7, is used to construct a spectral chart. The method has been tested in several flows and found to be reliable. In particular, it is tested on the axis of a slightly heated round jet, where 𝜀_k and 𝜀_θ can be estimated accurately via the budgets of k and ⟨𝜃²⟩/2, and the agreement between these estimates and the spectral chart results is almost perfect.]]> Wed 14 Dec 2022 15:55:53 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21391 λ is sufficiently large. The method is in fact applied to the lower wavenumber end of the dissipative range thus avoiding most of the problems due to inadequate spatial resolution of the velocity sensors and noise associated with the higher wavenumber end of this range.The use of spectral data (30 ≤ R_λ ≤ 400) in both passive and active grid turbulence, a turbulent mixing layer and the turbulent wake of a circular cylinder indicates that the method is robust and should lead to reliable estimates of ⟨ε⟩ in flows or flow regions where the first similarity hypothesis should hold; this would exclude, for example, the region near a wall.]]> Sat 24 Mar 2018 08:05:03 AEDT ]]>