Due to the particular features that appear in the vector maps delivered by the PIV method, there are postprocessing steps that can substantially enhance its performance. These steps include: detection of false vectors, correction of these vectors and the calculation of derived flow magnitudes. Many derived magnitudes can be of interest but this work focuses on the calculation of the first spatial derivative, component of flow divergence or vorticity, on a two-dimensional flow configuration. New algorithms, developed for each step, are described, with the aim of jointly applying them in a coherent way. Where applicable, an analytical tool for filter analysis and design is explained. Application to synthetic and real PIV data is presented as well as a performance contrast with other conventional algorithms, in terms of accuracy, frequency response and error propagation, among others.

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PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and performance, namely peak-locking and contemporary CCD camera read-out errors. Although the procedures are of general application to PIV, they are applied to a particular real case, giving an example of the methodology steps and the improvement in results that can be obtained. This real case corresponds to an ensemble of hot high-speed coaxial jets, representative of the civil transport aircraft propulsion system using turbofan engines. Errors of ∼0.1 pixels displacements have been assessed. This means 10% of the measured magnitude at many points. These results allow the uncertainty interval associated with the measurement to be provided and, under some circumstances, the correction of some of the bias components of the errors. The detection of conditions where the peak-locking error has a period of 2 pixels instead of the classical 1 pixel has been made possible using these procedures. In addition to the increased worth of the measurement, the uncertainty assessment is of interest for the validation of CFD codes.

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