French
English
Flow turbulence plays a crucial role in the performance of all turbomachinery components (affecting the heat transfer, boundary layer development, losses) and its characterization is fundamental in all levels of wind tunnel testing (from linear cascade testing to complete component testing). Experimental turbulence data are also required to provide boundary conditions for numerical simulations, as well as validation data. Nevertheless, the experimental characterization of turbulence is a challenging task, as it requires demanding measurements in terms of quality and resolution. This task is even more challenging in high speed and complex flows like turbomachinery flows, due to the limitations of measurement techniques in such environments.
In this context, the goal of this work is to develop a series of tools for improved turbulence measurements in challenging flow environments, typical of industrial applications. The focus is placed on intrusive measurement techniques which are of wide application in both industry and academia: Constant Temperature Hot Wire Anemometry and fast response pressure probes. The aforementioned techniques have been analyzed in terms of calibration, application and post-processing methods with the aim of reducing measurement errors. Particular focus has been placed on the techniques’ dynamic response. An uncertainty quantification methodology for turbulence measurements is also proposed in this work. It takes into account both the measurement uncertainty and the statistical uncertainty budgets and it can provide the evaluation of confidence intervals for all quantities of interest. Finally, two test cases are presented, showcasing the implementation of the developed concepts in a practical application and demonstrating the performance of turbulence measurements in a complex environment, also in terms of data reduction and processing methodologies.
Dr. Elissavet Boufidi
Research Engineer, Von Karman Institute