Effect of Tube Diameter on Wall Shear Stress Measurements Using Preston Tubes

Abstract The effect of tube diameter (d) on wall shear stress (τw) measurements using Preston tubes has been investigated in a zero pressure gradient turbulent boundary layer. Five different outside diameter tubes of 1.46, 1.82, 3.23, 4.76 and 5.54 mm, corresponding to (d/δ) of 0.022, 0.027, 0.048, 0.071 and 0.082 were used to measure τw at Reynolds numbers based on momentum thickness (Rθ) of 2800 to 4100. The calibration …