Obtaining accurate mean velocity measurements in high Reynolds number turbulent boundary layers using Pitot tubes
This article reports on one component of a larger study on measurement of the zero-pressure-gradient turbulent flat plate boundary layer, in which a detailed investigation was conducted of the suite of corrections required for mean velocity measurements performed using Pitot tubes. In particular, the corrections for velocity shear across the tube and for blockage effects which occur when the tube is in close proximity to the wall were investigated using measurements from Pitot tubes of five different diameters, in two different facilities, and at five different Reynolds numbers ranging from Re_θ = 11 100 to 67 000. Only small differences were found amongst commonly used corrections for velocity shear, but improvements were found for existing near-wall proximity corrections. Corrections for the nonlinear averaging of the velocity fluctuations were also investigated, and the results compared to hot-wire data taken as part of the same measurement campaign. The streamwise turbulence-intensity correction was found to be of comparable magnitude to that of the shear correction, and found to bring the hot-wire and Pitot results into closer agreement when applied to the data, along with the other corrections discussed and refined here.
© 2013 Cambridge University Press. Received 5 March 2012; revised 31 August 2012; accepted 27 October 2012. This work was made possible by financial support from the Australian Research Council, the Linn´e FLOW centre, and ONR under Grant N00014-09-1-0263. Partial support was also provided by the NASA Space Grant Program. The authors would also like to thank Anand Ashok, K. Chauhan, K. Dressler, G. Elsinga, S. Imayama, T. Kurian, R. Mathis, M. Matsubara, P. Monkewitz, H. Ng, E. Robert, P. Rozier, J.-D. Rüedi, A. Talamelli, Y. Tsuji and M. Vallikivi for their assistance and support throughout the course of setting up, conducting and analysing the experiments performed over the course of this measurement campaign.
Published - S0022112012005381a.pdf