TY - GEN
T1 - Interaction of a train of vortex pairs with a laminar boundary layer
AU - Yehoshua, Tal
AU - Seifert, Avi
PY - 2006
Y1 - 2006
N2 - The interaction between high amplitude, zero-net-mass-flux, periodic excitation, emanating from a slot in a plate and a laminar boundary layer was studied experimentally, in nominally two-dimensional flow and actuation conditions. The measurements included PIV, hot-wire, pressure, temperature and actuator displacement. The study was aimed at improved physical understanding of the generation of high amplitude fluidic excitation and its interaction process with the shear flow to be controlled. Several boundary conditions at the actuator exit slot were considered. These focused on three relative directions between the excitation and the incoming laminar boundary layer over a wide range of excitation parameters. When the actuator is operated in still air, and the excitation emanates perpendicular to the wall, a sequence of quasi 2D vortex pairs is generated, due to the extreme shear at the edges of the ejected flow during the blowing part of the cycle. The evolution of these vortices was studied in detail, and published previously, also for shallow relative angle between the excitation and the wall. The current paper is focused on detailed documentation of the interaction between excitation emanating at different directions to the incoming laminar cross-flow boundary layer. The main purpose of the study is providing future computational and modeling efforts a comprehensive database for comparison and validation as well as providing guidelines for successful and efficient active flow control implementation.
AB - The interaction between high amplitude, zero-net-mass-flux, periodic excitation, emanating from a slot in a plate and a laminar boundary layer was studied experimentally, in nominally two-dimensional flow and actuation conditions. The measurements included PIV, hot-wire, pressure, temperature and actuator displacement. The study was aimed at improved physical understanding of the generation of high amplitude fluidic excitation and its interaction process with the shear flow to be controlled. Several boundary conditions at the actuator exit slot were considered. These focused on three relative directions between the excitation and the incoming laminar boundary layer over a wide range of excitation parameters. When the actuator is operated in still air, and the excitation emanates perpendicular to the wall, a sequence of quasi 2D vortex pairs is generated, due to the extreme shear at the edges of the ejected flow during the blowing part of the cycle. The evolution of these vortices was studied in detail, and published previously, also for shallow relative angle between the excitation and the wall. The current paper is focused on detailed documentation of the interaction between excitation emanating at different directions to the incoming laminar cross-flow boundary layer. The main purpose of the study is providing future computational and modeling efforts a comprehensive database for comparison and validation as well as providing guidelines for successful and efficient active flow control implementation.
UR - http://www.scopus.com/inward/record.url?scp=84866886297&partnerID=8YFLogxK
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AN - SCOPUS:84866886297
SN - 9781604235203
T3 - Technion Israel Institute of Technology - 46th Israel Annual Conference on Aerospace Sciences 2006
SP - 208
EP - 237
BT - Technion Israel Institute of Technology - 46th Israel Annual Conference on Aerospace Sciences 2006
T2 - 46th Israel Annual Conference on Aerospace Sciences 2006
Y2 - 1 March 2006 through 2 March 2006
ER -