Application of an acoustic particle flux profiler in particle-laden open-channel flow

An acoustic particle flux profiler (APFP) has been used to non-intrusively and simultaneously profile the instantaneous concentration and the 2-D velo city vector in particle-laden open-channel flow. A temporal resolution of 0 .04s and a spatial resolution of phi 14.2x4.5mm(3) have been achieved by ca refully choosing the APFP parameters. The performance of the APFP has been investigated in mio flows under capacity charge conditions. The measured re sults for the mean profiles of velocity, velocity variance, Reynolds stress , concentration, particle flux, moment flux, diffusion coefficients, etc., are compared with the theoretical or semi-empirical formulas. Good agreemen t has been found. The fluctuation fields of velocity and concentration are highly correlated. Two kinds of coherent structures, the ejection and the i nrush, are found to be the dominant structures in the outer region which ar e responsible for particle entrainment, resuspension and deposition in a pa rticle-laden flow. It is concluded that the recently developed APFP is a po werful non-intrusive instrument for sediment transport studies in open-chan nel now and that it works well under capacity charge conditions where other instruments have difficulties. It provides rich information on the details of flow structures and of particle-turbulence interactions.