UNSTEADY PRESSURE FIELD AROUND OSCILLATING PRISM PREDICTED BY LES

Unsteady velocity-pressure fields around an oscillating square prism a re analyzed by means of Large Eddy Simulation (LES). The accuracy of t he numerical results is assessed by comparing them with the experiment al results of Bearman et al.[3]. The prism is forced to oscillate in a sinusoidal motion in the x2(lateral) direction. In order to incorpora te the influence of the body motion, an inertia force term, whose magn itude is equal to the acceleration of the body, but with the opposite sign, is added to the transport equation of u2BAR, as an external forc e at each grid point of the fluid. The reduced velocity, U0/N(p)D, in this study ranges from 7.5 to 10.0. It was confirmed that the numerica l results successfully reproduce the lock-in phenomena in this,range. Furthermore, the results of LES showed a good agreement with the resul ts of experiment, in terms of : 1) the phase angle between the displac ement of the oscillating prism and the negative pressure acting on the side face, and 2) the correlation between pressures across the side f ace.