Synchronization of turbulence in channel flow

Synchronization of turbulence in channel flow is investigated using continuous data assimilation. The unknown within a region the channel. Beyond this velocity field provided, and directly prescribed simulation, while pressure throughout entire domain. takes place when simulation recovers full true state flow, or other words missing accurately re-established, spontaneously. Successful synchronization depends on orientation, location size layer. For friction Reynolds numbers up to one thousand, wall-attached horizontal layers can synchronize as long their thickness less than approximately thirty wall units. When layer detached from wall, critical increases with height proportional local wall-normal Taylor microscale. A flow-parallel, vertical that spans synchronizes its spanwise width order near-wall microscale, criterion for crossflow set by advection distance Lyapunov time scale. Finally, we demonstrate possible only planar are available, rather outer state, satisfies condition direction. These numerical experiments capacity reconstructing, synchronizing, scales observations,