Development of the data assimilation method suitable for large-eddy simulation model using the vibration equation

Nakayama, Hiromasa   ; Takemi, Tetsuya*

We proposed the data assimilation method using the vibration equation suitable for LES models. First, we generated the basic turbulent boundary layer (TBL) flow with a power law exponent of 0.14 at the upstream area and then attempted to nudge toward the TBL flow with a power law exponent of 0.25 by our proposed data assimilation. For a case that the natural frequency set in the vibration equation was larger than the peak frequency of the basic TBL flow, the turbulent fluctuations were rapidly damped although the mean velocity profile matched with the target one. On the other hand, for a case that the natural frequency was smaller than the peak frequency, the mean wind velocity profile was reasonably nudged toward the target profile while maintaining the turbulent fluctuations. It is concluded that our proposed data assimilation method using the vibration equation successfully nudges toward the target mean winds with small-scale turbulent fluctuations.