运动追踪增强方法应用于湍动剪切流层析PIV测量的性能研究
The motion tracking enhancement technique(MTE) is a recently introduced method to improve theaccuracy of tomographic PIV measurements at seedingdensity higher than currently practiced. The workingprinciple is based on the fact that the particle field and itsprojections are correlated between the two exposures.Therefore, information from subsequent exposures can beshared within the tomographic reconstruction process of asingle object, which largely reduces the energy lost intoghost particles. The study follows a previous work basedon synthetic particle images, showing that the MTE techniquehas an effect similar to that of increasing the numberof cameras. In the present analysis, MTE is applied toTomographic PIV data from two time-resolved experimentson turbulent shear flows: a round jet at Re = 5,000(facq = 1,000 Hz) and a turbulent boundary layer at thetrailing edge of an airfoil (Rec = 370,000) measured at12,000 Hz. The application of MTE is extended to the caseof more than two recordings. The performance is assessedcomparing the results from a lowered number of cameraswith respect to the full tomographic imaging system. Theanalysis of the jet flow agrees with the findings ofnumerical simulations provided the results are scaled takinginto account the concept of MTE efficiency based onthe volume fraction where ghost-pairs (Elsinga et al.2010a) are produced.