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ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
INVESTIGATION OF THE TURBULENT BOUNDARY LAYER PERTURBED BY A TRIANGULAR RIPPLE
Submission Author:
Erick de Moraes Franklin , SP , Brazil
Co-Authors:
Fernando David Cúñez
Presenter: Erick de Moraes Franklin
doi://10.26678/ABCM.ENCIT2016.CIT2016-0047
Abstract
Turbulent boundary layers over flat walls perturbed by low hills are frequently found in industry and nature. In industry, some examples are the flows over sand ripples and dunes (which have a triangular shape) in closed conduits such as petroleum pipelines. In the present study, experiments have been performed for the investigation of the perturbation of a fully-developed turbulent boundary layer by a two-dimensional hill of triangular shape. Different water flows were imposed over an asymmetric triangular hill fixed on the bottom wall of a closed conduit, and the flow field was measured by PIV (Particle Image Velocimetry). Reynolds numbers based on the channel height varied between 27500 and 35000 and the regime was hydraulically smooth. From the instantaneous flows fields, the mean velocities and fluctuations were computed, and the shear stress over the ripple could be determined. The general behaviors of obtained velocities and stresses are compared to published asymptotic analyses and the surface shear stress is discussed in terms of bed stability.
Keywords
Turbulent flow, experimental development
