- Title
- Temperature correlations with vorticity and velocity in a turbulent cylinder wake
- Creator
- Chen, J. G.; Zhou, Y.; Antonia, R. A.; Zhou, T. M.
- Relation
- International Journal of Heat and Fluid Flow Vol. 84, Issue August 2020, no. 108606
- Publisher Link
- http://dx.doi.org/10.1016/j.ijheatfluidflow.2020.108606
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2020
- Description
- This work aims to understand the difference in the correlations between the fluctuating temperature and the vorticity from that between the fluctuating temperature and the velocity in a turbulent cylinder near wake. Measurements are made at x/d = 10, 20 and 40, where x is the streamwise distance from the cylinder axis and d is the cylinder diameter, with a Reynolds number of 2.5×103 based on d and the free-stream velocity. The three components of the fluctuating velocity vector ui(i = 1, 2 and 3), vorticity vector ωi (i = 1, 2 and 3), and temperature θ in the plane of the mean shear are measured simultaneously with a multi-wire probe consisting of four X-hotwires and four cold wires. It is found that at x/d = 10, both correlations between uiand θ and between ωi and θ predominantly take place at St = 0.21, due to the concentric distribution of the Kármán vortices and the heat. With increasing x/d, the correlation between ωi (i = 1, 2 and 3) and θ drops rapidly, as a result of the weakened Kármán vortices; in contrast, the correlation between u1 and θ increases appreciably, largely due to an enhanced correlation between u1 and θ at low frequencies or scales of motions larger than the Kármán vortex. The slowly decreasing (along x) two-point autocorrelations of u1 and θ suggest that the very-large-scale motions (VLSMs) found in wall flows occur also in the turbulent wake and are responsible for the high correlation between u1 and θ at low frequencies.
- Subject
- velocity; vorticity; temperature correlation; wall flows
- Identifier
- http://hdl.handle.net/1959.13/1434828
- Identifier
- uon:39519
- Identifier
- ISSN:0142-727X
- Language
- eng
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