Mach and Reynolds Number Effects on the Wake Properties of Microramps

A parametric study has been conducted into the effects of device height (h=6−10  mm), Mach number (M∞=1.5−2.5), and Reynolds number (Re∞=28×106 to 63×106  m−1) on the effectiveness of microramp vortex generators as flow control devices. The control authority of the microramp comes from the two count...

Full description

Saved in:
Bibliographic Details
Published in:AIAA journal 2016-11, Vol.54 (11), p.3481-3494
Main Authors: Giepman, Rogier H. M, Srivastava, Aabhas, Schrijer, Ferry F. J, van Oudheusden, Bas W
Format: Article
Language:English
Subjects:
Boundary layers
Control equipment
Flow control
Fluid dynamics
Fluid flow
Mach number
Momentum
Particle image velocimetry
Reynolds number
Velocity distribution
Vortex generators
Vortices
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A parametric study has been conducted into the effects of device height (h=6−10  mm), Mach number (M∞=1.5−2.5), and Reynolds number (Re∞=28×106 to 63×106  m−1) on the effectiveness of microramp vortex generators as flow control devices. The control authority of the microramp comes from the two counter-rotating vortices it introduces into the boundary layer. The vortices transport high-momentum fluid toward the wall, thus creating a fuller velocity profile that is less prone to separation. This momentum transport, however, comes at the price of a low-momentum wake that is formed downstream of the device. The induced flowfield has been studied by means of two-dimensional particle image velocimetry, oil-flow, and schlieren visualizations. Most of the geometric flow features were found to scale linearly with microramp height h: the wake height, wake strength, vortex core height, and the momentum flux added to the near-wall region of the flow all increase linearly with h. The control effectiveness of the microramp in the symmetry plane is reduced for higher Mach numbers (M∞=2.5) as the strength of the vortices is reduced, which adds less momentum to the near-wall region of the flow. Also, a stronger wake is recorded for the higher Mach number cases. Only a weak Reynolds number effect is observed, with the microramp becoming slightly more effective at higher Reynolds numbers.
ISSN:0001-1452
1533-385X
DOI:10.2514/1.J054947