Passive scalar and velocity fields in a turbulent cylinder near wake

Abstract

This work aims to provide an exploration of the spectral analogy between the enstrophy and the scalar dissipation rate, as well as between the passive scalar and the velocity vector fluctuations, especially in the context of the highly organized aspects that exist in the near wake. Measurements were taken in the wake of a heated circular cylinder at x/d = 10–40, with a Reynolds number of 2540. The resutls indicate that there is a reasonable analogy between the spectra corresponding to enstrophy and passive scalar dissipation rate, the small departures being caused by coherent motions. The spectral analogy between the streamwise velocity fluctuation u and the passive scalar θ is better than that between the velocity fluctuation vector q and θ. This is also closely related to the highly organised lateral velocity fluctuation v in this flow.