流体中速度场,压力场检测方案(粒子图像测速)

Introduction Particle image velocimetry (PIV) has proven its strength as a flow diagnostic tool to characterise instantaneous velocity fields and derived quantities such as vorticity. Recent efforts apply momentum conservation principles on planar velocity data in order to extract more quantities, such as pressure fields and integral aerodynamic forces. The theoretical concepts for this 憄lanar pressure imaging? (PPI) have been established and its practical implementation for steady (or time-averaged) flows under approximately 2D flow conditions has been demonstrated (e.g. Baur and K鰊geter 1999, Gurka et al. 1999, Oudheusden et al. 2007). The next challenge is to extend PPI to unsteady flows. This extension can be done on basis of time-resolved flow diagnostics such as time-resolved PIV (TR-PIV), cf. Kurtulus et al. 2007. Instantaneous pressure fields are particularly interesting in bluff-body flows and in fluid-structure interactions, both are important in e.g. wind-engineering applications. A serious complication in extending the planar approach is that flows tend to develop 3D instantaneous structures even for nominally 2D configurations, especially at larger Reynolds numbers.