DOI: 10.1615/TSFP6
PRESSURE/VELOCITY COUPLING INDUCED BY A NEAR WALL WAKE
Краткое описание
The modification of the near wake structure of a disk in vicinity to a wall and its coupling with the spatio-temporal properties of the fluctuating wall pressure field is investigated using PIV and multi-points pressure measurements. A strong interaction is indeed observed for the value of the gap ratio H/D = 0.75 studied here. The magnitude of the wall fluctuating pressure is significant and a large band contribution is associated to the wake unsteady structure and turbulence. The characteristic frequency of the vortex shedding from the disk is a strong constraint for the wall fluctuating pressure. Spatio-temporal velocity and pressure/velocity correlations carry the signature of the periodicity associated with vortex shedding. However, significant phase differences are observed between the velocity components and the fluctuating wall pressure. These phase differences are moreover different for each velocity components. Spatial or spatio-temporal LSE and QSE of the velocity field from the pressure data are finaly computed. A major improvement is obtained when a spatio-temporal evolution of the pressure base is kept for estimation.