Suppression of the Near Wall Burst Process of a Fully Developed Turbulent Pipe Flow
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
Pagination or Media Count:
A local suppression of the near wall region burst process is achieved by modifying the buffer region and sublayer Y 30 of a fully developed turbulent pipe flow with a 16.4 wall unit high, wall-mounted bump. A downstream converging flow field is produced by the divergence of the approaching mean flow around the bump. In addition, a pair of counter-rotating vortices are generated by the bump and convected downstream. The vortices have a circulation which produces a common wall directed flow between them, which also contributes to the flow convergence. These vortices are 10 to 15 wall units in diameter and persist for more than 174 wall units downstream. The investigation is conducted in the ARLPSU glycerin tunnel at a Reynolds number, based on pipe diameter, of approximately 10,000. The momentum thickness Reynolds number is 730. Multicomponent, multi-point, time resolved laser Doppler velocimetry measurements are made in both the undisturbed and modified boundary layers. The measurements include single-point three-component velocity profiles, two-point multi-component velocity correlations and velocity spectral estimates.
- Fluid Mechanics