{'fraction_non_alphanumeric': 0.008524590163934427, 'fraction_numerical': 0.0013114754098360656, 'mean_word_length': 4.758490566037736, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
LDA measurements and CFD simulation of an annular impinging jet

Laser Doppler anemometry (LDA) is a useful experimental tool which is capable of providing high quality data for validating Computational Fluid Dynamic (CFD) simulations. Previous work with a mixed-flow pump had shown that there is a considerable discrepancy between the LDA data and the CFD simulation if the standard turbulence model is not modified to allow for the additional effect of the centrifugal action. Prior to the investigation of a cyclone separator in which the flow has a very high centrifugal action, it was decided to investigate a simpler flow consisting of an annular jet impinging on a flat plate in which the curvature of the jet can be controlled by the distance between the jet exit and the impinging plate. By comparing the results of LDA and simulation of the annular jet with different amounts of curvature it was expected that a transition level would be found at which a modified model would be required. The flow from an annular jet impinging on a plate can be simply analyzed in terms of the internal pressure which is generated by the rate of change of momentum due to the jet being turned through 90 degrees. However the detailed velocity distribution and variation of pressure across the jet cannot be obtained from simple analysis and require the use of a CFD code. The commercial code PHOENICS has been used in this investigation and the experimental data was obtained using a DANTEC single component fiber optic LDA system.