Signal Postprocessing Techniq ue and Uncertainty Analys is of ADV Turbulence Measurements on Free Hydraulic Jumps

ROMAGNOLI, M.; GARCÍA, C.M.; LOPARDO, R.

JOURNAL OF HYDRAULIC ENGINEERING

ASCE-AMER SOC CIVIL ENGINEERS

Año: 2012 vol. 138 p. 800 - 808

0733-9429

This note presents experimental results on an error analysis of ADV turbulencemeasurements in free hydraulic jumps incorporating recent ADV signal processingtechnique. This works aims to quantify the influence of each error source in acousticDoppler measurements (i.e. presence of spikes, Doppler noise and filtering effects dueto the ADVs´ sampling strategy) on the variance and integral time scale computationsas well as defining the corresponding confidence interval for each reported value.Experiments were conducted for an upstream Froude number of 3.0.The relative error contribution of each source to both raw longitudinal variance (RECV)and raw longitudinal integral time scale (RECT) decreases downstream.Inside the zone where aeration effects and high turbulence levels are relevant, Dopplernoise constitutes the most important error source. Further downstream, where aerationeffects and turbulence levels diminish, the error produced by the presence of spikescan be neglected while effects of both Doppler noise and ADVs´ sampling strategy arebalanced.The relative confidence interval for corrected longitudinal variance ranges between30% and 10% while relative uncertainty level for corrected longitudinal integral timescale varies from 80% to 50%. The results of this study point out the requirement foradequate signal post-processing technique and uncertainty analysis of ADV turbulencemeasurements.