Abstract
The Preston's method is considered as one of the many ways to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure of the Preston tube and undisturbed static pressure, combined with calibration curves, which depend on the Preston tube diameter, fluid density, and viscosity. Since its invention, no significant advancement in theory has been made, and calibration curves proposed by Preston (1954),Patel (1964) ,Bechert (1995) are still in use. In the present study, a need to measure surface shear stress over a circular cylinder prompted us to develop our original Preston tube system. The developed system has been calibrated by measuring the wall shear stress in the fully developed turbulent flow regime in a circular pipe. The present results confirm the previously reported calibration curves.
