There are many experimental results about the lock-on around circular, square, and plate in various forcing conditions. And some results on heat and mass transfer in pulsating flows is also concern of recent research. But numerical study of unsteady flow is a difficult problem to figure out the lock-on. Some show the possibility of numerical simulation in unsteady flow. And the benchmark of numerical simulation is the lock-on.
Steady upstream with free-stream pulsation is a major concern of this paper. A numerical study is made by FSM for unsteady cylinder flows. This paper is concentrated on the lock-on and the effect of the lock -on in Mass-Transfer. So, this paper shows the region of lock-on in slop 1/1, 1/2, 1/3, and why does the lock-on occur, and shows the distribution of time-averaged Sherwood number around the cylinder in lock-on. In addition, the forcing frequency dependency of drag-coeff., lift-coeff., and space-averaged Sherwood number will be shown in FFT.
