Wall shear stress and pressure distributions of developing turbulent oscillatory flows in a square sectional curved duct

In the present study, flow characteristics of turbulent oscillatory flow in a square-sectional 180 .deg. curved duct are investigated experimentally. In order to measure wall shear stress and pressure distributions, experimental studies for air flow are conducted in a square-sectional 180 deg. curved duct by using the LDV system with the data acquisition and the processing system. The wall shear stress measuring point bend angle of the 150 .deg. and pressure distribution of the inlet (φ=0 .deg.) to the outlet (φ=180 .deg.) at 10 .deg. intervals of the duct. The results obtained from the experimentation are summarized as follows: A wall shear stress value in an inner wall is larger than that in an outer wall, except for the phase angle (ωt/π/6) of 3, because of the intensity of secondary flow. The pressure distributions are the largest in accelerating and decelerating regions at the bend angle(φ) of 90 .deg. and pressure difference of inner and outer walls is the largest before and after the φ=90 .deg.