Large-eddy simulation of flat-plate boundary layers in favorable pressure gradients (FPG) are performed for two different acceleration parameters. The high-acceleration case is in good agreement with the experimental data by Fernholz and Warnack. Substantial reduction in turbulent kinetic energy, strong decorrelation of u and v fluctuation, and a reduction of the bursting frequency indicate that the accelerated boundary layer is in a laminar-like state when the pressure-gradient parameter K exceeds a threshold value. Downstream of this region, the boundary layer has a fast re-transition to turbulence: it seems due to the turbulent structures present in the outer part of the boundary layer. In the low K case, the boundary layer does not depart significantly from equilibrium.
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