Self-similar evolution of velocity and temperature small scales in a turbulent round jet

Kinetic energy and temperature dissipation were measured on the centerline axis of a jet where the flow was heated slightly so that temperature was considered as a passive scalar. A very good collapse of kinetic energy evolution was observed for different Reynolds numbers. For temperature dissipation decay along the jet centerline, a power law relationship was tested for all Reynolds numbers. Similarity laws for Taylor and Corssin length scales (λ,λθ) and Kolmogorov length scales (ηk,ηθ) were verified for different Reynolds numbers, and their validity regions were identified. The ratios ηk/λ and ηθ/λθ were found to reach an asymptotic value of 0.4. Velocity and temperature small scale statistic similarities were achieved in the measurement domain. For the dynamic field, Rλ reached an asymptotic value of ∼1.51Rj1/2 at χ∼15. For the scalar, the turbulent Peclet number Pe reached a constant value further downstream (χ∼25) than Rλ (Pe∼0.6Rj1/2 and ∼0.4Rλ).