Abstract for a paper presentation at the

for a paper presentation at the 12th international symposium on applications of laser techniques to fluid mechanics Investigation of film flow by means of μ-PIV P. Schober, B. Richter, O. Schäfer and K. Dullenkopf Lehrstuhl und Institut für Thermische Strömungsmaschinen (ITS) Universität Karlsruhe Germany Shear-driven liquid wall films play a major role in the fuel preparation process in state of the art prefilming gas turbine combustor nozzles. Advanced two-phase flow CFD-codes have been identified as a valuable tool in the design and the optimisation process of these components. To simulate the interaction of the liquid film and the air flow within complex geometries, e.g. airblast atomisers, a detailed understanding of the dynamics inside the shear driven liquid film is needed. Mean film heights of less than 100 microns and a rough wavy film surface hamper the application of measurement techniques. Previous investigations have led to the assumption, that most of the film liquid is transported in waves rolling on a viscous sub-layer. Experiments with a modified μ-LDV system ([1], [2]) enabled for the first time the validation of this model. A direct numerical simulation of Burkhard [3] additionally supports the experimental results. To finally proof the model assumption, a planar measurement technique would be advantageous, which overcomes the inherent uncertainty in the assigning of punctual LDV data points to a location inside a defined standard wave, as shown in Fig. 1.