Quantifying eddy structures and very-large-scale motions in turbulent round jets
| Autor: | Andrew Pollard, Milad Samie, Philippe Lavoie |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
Jet (fluid) Scale (ratio) Turbulence Mechanical Engineering Flow (psychology) Boundary (topology) Reynolds number Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Computational physics Physics::Fluid Dynamics Azimuth Wavelength symbols.namesake Mechanics of Materials 0103 physical sciences symbols 010306 general physics |
| Zdroj: | Journal of Fluid Mechanics. 916 |
| ISSN: | 1469-7645 0022-1120 |
| DOI: | 10.1017/jfm.2021.183 |
| Popis: | Coherent structures in turbulent round jets are evaluated for a jet Reynolds number up to in the axial, radial and azimuthal directions is observed. The other spectral domain, indicated by large wavelengths, is associated with very-large-scale motions (VLSMs). The wavelength marking the boundary between these spectral domains is used to decompose the velocity fluctuations into ES and VLSM components, and the corresponding ES and VLSM components of two-point correlations are obtained from the experimental data. The VLSM component of two-point correlations denotes helical structures as the dominant VLSMs in the jet turbulent region. Instantaneous axial velocity fluctuation fields from DNS support the prevalence of helical VLSMs in the jet. Moreover, the ES signatures are evident in the unwrapped axial–azimuthal planes of the DNS, indicating that the VLSMs are formed by the concatenation of ESs. Consistent with the experimental two-point correlations and DNS flow fields, a conceptual model is proposed for the ESs and VLSMs, which illustrates their arrangements. |
| Databáze: | OpenAIRE |
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