Abstract
In this paper, response characteristics of three types of rectangular block in three kinds of non-shear flow or flow without velocity gradient-one is smooth flow and others are turbulent flows-are presented. Furthermore the predominant strouhal numbers, S_p, by measuring the unsteady velocity fluctuations in the wake in smooth flow are also shown. Main results are as follows. 1) The effect of the vortex-shedding on the response was found to be large. 2) Great differences were found in the response characteristics between at lower reduced velocity and in vicinity of the critical reduced velocity. i) At lower reduced velocities the response intensity increased monotonically with the velocity. An increase of turbulence intensity raised the response intensity. ii) In vicinity of the critical reduced velocity (≡1/S_p), the self-excited vibration (α≧75deg.) and the restricted vibration prior to it were observed. Here, the problem aroud the critical reduced velocity was in vestigated in cases of MODEL 8×4, 8×2; α≧70 deg..
