Abstract
The precise modeling of turbulence is indispensable for weather forecasting and environmental heat-removal and pollution-dispersion assessment. Models rely on correlations derived from field measurements. Unfortunately, the readings are usually contaminated with mesoscale motions which alter turbulence statistics and mislead the characterization of turbulence coherent structures, the drivers of the heat and mass transport process. This article depicts the interference of the mesoscales in turbulence statistics and coherent structure detection. Atmospheric measurements were taken at EKOMAR on the east coast of Malaysia. Two ultrasonic anemometers at heights of 1.7 and 12 m were utilized. Twelve samples from the convective atmospheric boundary layer were analyzed. Spectral and auto-correlation analysis were conducted to assess the weight of the mesoscales relative to the shear coherent structure scales. The structure inclination angle and timescale were calculated for the wind speed signal with and without the mesoscale scales filtered out. It was found that these interfering structures largely shifts the calculated length- and time-scales of the coherent structures. The improper filtration of the signal may delete part of the coherent structures and hence worsen the situation.
| Original language | English |
|---|---|
| Article number | 178 |
| Journal | Journal of the Brazilian Society of Mechanical Sciences and Engineering |
| Volume | 40 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Apr 2018 |
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Keywords
- Atmosphere
- Coherent structures
- Turbulence
ASJC Scopus subject areas
- Mechanical Engineering
Cite this
Modulation of the atmospheric turbulence coherent structures by mesoscale motions. / Lotfy, Eslam Reda; Zaki, Sheikh Ahmad; Harun, Zambri.
In: Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 40, No. 4, 178, 01.04.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Modulation of the atmospheric turbulence coherent structures by mesoscale motions
AU - Lotfy, Eslam Reda
AU - Zaki, Sheikh Ahmad
AU - Harun, Zambri
PY - 2018/4/1
Y1 - 2018/4/1
N2 - The precise modeling of turbulence is indispensable for weather forecasting and environmental heat-removal and pollution-dispersion assessment. Models rely on correlations derived from field measurements. Unfortunately, the readings are usually contaminated with mesoscale motions which alter turbulence statistics and mislead the characterization of turbulence coherent structures, the drivers of the heat and mass transport process. This article depicts the interference of the mesoscales in turbulence statistics and coherent structure detection. Atmospheric measurements were taken at EKOMAR on the east coast of Malaysia. Two ultrasonic anemometers at heights of 1.7 and 12 m were utilized. Twelve samples from the convective atmospheric boundary layer were analyzed. Spectral and auto-correlation analysis were conducted to assess the weight of the mesoscales relative to the shear coherent structure scales. The structure inclination angle and timescale were calculated for the wind speed signal with and without the mesoscale scales filtered out. It was found that these interfering structures largely shifts the calculated length- and time-scales of the coherent structures. The improper filtration of the signal may delete part of the coherent structures and hence worsen the situation.
AB - The precise modeling of turbulence is indispensable for weather forecasting and environmental heat-removal and pollution-dispersion assessment. Models rely on correlations derived from field measurements. Unfortunately, the readings are usually contaminated with mesoscale motions which alter turbulence statistics and mislead the characterization of turbulence coherent structures, the drivers of the heat and mass transport process. This article depicts the interference of the mesoscales in turbulence statistics and coherent structure detection. Atmospheric measurements were taken at EKOMAR on the east coast of Malaysia. Two ultrasonic anemometers at heights of 1.7 and 12 m were utilized. Twelve samples from the convective atmospheric boundary layer were analyzed. Spectral and auto-correlation analysis were conducted to assess the weight of the mesoscales relative to the shear coherent structure scales. The structure inclination angle and timescale were calculated for the wind speed signal with and without the mesoscale scales filtered out. It was found that these interfering structures largely shifts the calculated length- and time-scales of the coherent structures. The improper filtration of the signal may delete part of the coherent structures and hence worsen the situation.
KW - Atmosphere
KW - Coherent structures
KW - Turbulence
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U2 - 10.1007/s40430-018-1109-5
DO - 10.1007/s40430-018-1109-5
M3 - Article
VL - 40
JO - Journal of the Brazilian Society of Mechanical Sciences and Engineering
JF - Journal of the Brazilian Society of Mechanical Sciences and Engineering
SN - 1678-5878
IS - 4
M1 - 178
ER -