TY - GEN
T1 - Numerical simulation of clear air turbulence using 4D-var
AU - Misaka, Takashi
AU - Obayashi, Shigeru
AU - Endou, Eiichi
PY - 2007
Y1 - 2007
N2 - An unsteady flow phenomenon of clear air turbulence (CAT) was investigated by large eddy simulation (LES) using flight data available from airlines encounter with severe turbulence. To incorporate the flight data into the LES, the four-dimensional variational method (4D-Var) was employed. This paper presents formulation and numerical method of the 4D-Var applied to the flight data. The validation of the present method was conducted using pseudo-flight data obtained from reference flow field. Then, the 4D-Var was applied to two severe turbulence cases. Existing hazard indices, F-factor and root mean square (RMS) normal load were evaluated on the reproduced flow field. The validation results show reproducibility of flow field using limited measurements if the measurements include primary flow features. An unsteady flow of CAT was simulated by using the 4D-Var and the results show the existence of characteristic vortices which correspond to CAT.
AB - An unsteady flow phenomenon of clear air turbulence (CAT) was investigated by large eddy simulation (LES) using flight data available from airlines encounter with severe turbulence. To incorporate the flight data into the LES, the four-dimensional variational method (4D-Var) was employed. This paper presents formulation and numerical method of the 4D-Var applied to the flight data. The validation of the present method was conducted using pseudo-flight data obtained from reference flow field. Then, the 4D-Var was applied to two severe turbulence cases. Existing hazard indices, F-factor and root mean square (RMS) normal load were evaluated on the reproduced flow field. The validation results show reproducibility of flow field using limited measurements if the measurements include primary flow features. An unsteady flow of CAT was simulated by using the 4D-Var and the results show the existence of characteristic vortices which correspond to CAT.
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U2 - 10.2514/6.2007-81
DO - 10.2514/6.2007-81
M3 - Conference contribution
AN - SCOPUS:34250804903
SN - 1563478900
SN - 9781563478901
T3 - Collection of Technical Papers - 45th AIAA Aerospace Sciences Meeting
SP - 911
EP - 924
BT - Collection of Technical Papers - 45th AIAA Aerospace Sciences Meetin
PB - American Institute of Aeronautics and Astronautics Inc.
T2 - 45th AIAA Aerospace Sciences Meeting 2007
Y2 - 8 January 2007 through 11 January 2007
ER -