Structure function in lieu of correlation function
Using experimental data subject to noise and drift, we find the structure function can be computed to higher accuracy, yet using less data, than the correlation function. While this tendency is in line with theoretical reasoning, we seem to be the first to report on quantitative aspects. Taking wall pressure data from a transsonic wind tunnel, our structure functions are obtained with one to two orders less of data points than correlation functions of comparable information content. These advantages apply to auto- and cross-structure functions alike when compared to auto- and cross-correlation functions, respectively. Some comments are added on the possibility of designing digital “structurators” similar to existing digital correlators, either as software products using the FFT and recursive algorithms, or as hardware products in the form of fast special purpose paralled processors.
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