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| Titel |
Novel approaches to estimate turbulent kinetic energy dissipation rate from low and moderate resolution velocity fluctuation time series |
| VerfasserIn |
Marta Wacławczyk, Yong-Feng Ma, Jacek Kopeć, Szymon Malinowski |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143608
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| Publikation (Nr.) |
 EGU/EGU2017-7344.pdf |
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| Zusammenfassung |
| Evaluation of turbulent kinetic energy (TKE) dissipation rate (ε) from the low- and
moderate-resolution in situ airborne measurements is problematic and scarce. Due to various
problems related to e.g. inhomogeneity of turbulence along the aircraft and artifacts related to
inevitable aerodynamic problems, estimation of ε using the traditional methods such as power
spectra or structure functions are complex and far from being standardized. Therefore, we try
to introduce alternative methods to increase robustness of ε retrievals from such
low-resolution airborne measurements. In this study we propose two approaches to estimate
ε based on the zero-crossing method by Sreenivasan et al. (1983). The original
formulation requires a fine resolution of the measured signal, down to the smallest
dissipative scales. However, due to finite sampling frequency, as well as measurement
errors, velocity time series obtained from airborne experiments are characterized by
the presence of effective spectral cut-offs. In contrast to the original formulation
the proposed approaches are suitable for use with signals originated from such
experiments. The fittingness of the new approaches is tested using measurement
data obtained during the Physics of Stratocumulus Top (POST) airborne research
campaign.
Sreenivasan K., Prabhu A. and Narasimha R., 1983: Zero-crossings in turbulent signals, J.
Fluid Mech., 137, 251–272. |
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