Comparison of single and X-wire measurements of streamwise velocity fluctuations in turbulent boundary layer
More details
Hide details
Czestochowa University of Technology, Institute of Thermal Machinery, Częstochowa, Poland
Journal of Theoretical and Applied Mechanics 2014;52(2):499–505
The paper discusses the problem of measuring velocity fluctuations of a turbulent boundary layer using single and X-wire probes. It seems that the difference between the streamwise fluctuating component of these two probes results not only from spatial resolution, but also from influence of the wall-normal fluctuating component, which is usually not considered. It was shown that the vector summing these two components obtained from X-wire probe gives the shape of fluctuation distribution obtained from a single-wire probe. It implies that the underestimation of the near-wall peak of streamwise fluctuating component in X-wire measurements results from disregarded wall-normal fluctuations, which is obviously taken in the case of a single-wire probe. Moreover; it was shown that the criteria for wire length i.e. $ l^+\leq20$ could not be sufficient to properly estimate the streamwise and wall-normal fluctuations.