Author(s): Chaoquan Chen; Daoyi Chen

Linked Author(s):

Keywords: No Keywords

Abstract: The turbulent structure of oscillatory flows over rough and smooth bed was experimentally investigated in a shallow-water tidal flume using a LDV system. The test periods of oscillatory flow were 30s, 60s and 240s, and measurement at each point covered 50 tidal cycles. The velocity and turbulent properties were obtained through phase-averaged analysis. The profiles of mean velocity, turbulent intensity and Reynolds stress were shown at different phases in details. It is found the streamwise mean velocity near the bed can be approximated as logarithmic distributions with different integration constants for different oscillatory periods. The phase shift in different heights appeared in the profiles of the streamwise velocity, turbulent intensities and Reynolds stress with the leading phases near the bed. The peak value of turbulent intensity in vertical direction, which occurs in the outer region of the boundary layer, reaches its maximum within decelerating phases as the flow progresses during the course of the cycle. And the peak Reynolds stress occurs at the phase of more than 15 degree behind the peak streamwise velocity.

DOI:

Year: 2001