تعيين تنش برشي متوسط كف و جداره ي در كانال هاي مستطيلي صاف

Wall and bed shear stress in smooth rectangular channels

This Study reports on experiments concerning the boundary shear stress and boundary shear force distributions in a smooth rectangular channel. The boundary shear stresses were measured with a 4-raiti outside diameter Preston tube in conjunction with a differential pressure transducer. The calibration curves of PateJ (1965) were used to convert pressure reading to boundary shear stresses. Nonlinear regression-based equations are drive from experimental analysis to determine percentage of the total shear force carried by the walls and mean wall and bed shear stresses around wetted perimeter. The proposed equations compared to previous researches are shown to higher correlation coefficient and smaller standard deviation. Furthermore, single variable equations are introduced in the paper indeed an advantage compared to that of other studies.