Turbulent Flow in a Curved Duct with a Rectangular Cross-Section : 4th Report, Pulsatile Flow in a Fully Developed Flow Region

Abstract

The cross-sectional average velocity, U_m, of a pulsatile flow fluctuates with the Womersley number of 45.2. The ratio of the amplitude of U_m to its time mean value, U^^-_m, is 0.366 and the Dean-number, based on U^^-_m, is 1.58×10⁴. The results obtained are as follows : (1) The axial velocity componet, U_φ, fluctuates synchronously with U_m. The amplitude of U_φ is smaller than that estimated from a quasi-steady state assumption based on U_m at the outer wall region and is larger at the inner wall region. At the inner wall region the amplitude of secondary flow velocity component, U_r, becomes about two times larger than the estimated one using U_m : (2) In the large part of the skewed boundary layer on the end wall, non-dimensionalized secondary flow velocity decreases exponentially with distance from the end wall, although the distribution in steady flow has wall jet type similarity.