Session: K12-01: AEROSPACE HEAT TRANSFER I

Paper Number: 131457

131457 - Examining the Symmetry of a Turbulent Wake Arising From Asymmetric Turbulent Shear Layers: An Experimental and Analytical Study 

Abstract: 

The study examines asymmetry in boundary layers by measuring 2D turbulence in the wake of a flat plate. In contrast to previous studies, this work varies shear layer asymmetry using tripping wires while keeping the Reynolds number and pressure constant. Six distinct conditions are considered, encompassing the natural wake and asymmetric wakes for five different values of θ/θ₀ where θ represents the boundary layer momentum thickness and θ₀ represents the boundary layer momentum thickness of the symmetric turbulent-turbulent case respectively for upper half-width and lower half-width, measured at downstream position x/h. These conditions were studied to gain deeper insights into wake evolution and self-similarity. As the momentum thickness increased, noticeable changes were observed in the velocity profiles.  The asymmetric wake showed distinct differences, including a velocity defect ( where is edge velocity of the wake and and higher shear stress compared to the symmetric case. The study suggests the presence of long memory in wakes due to self-preserving states established by initial conditions. 

Developing analytic methods in conjunction with the Reynolds stress profile and Reynolds stress shape functions, we were able to formulate a self-similarity equation for the wake.

Keywords: Shear layer; Asymmetric turbulence; wake evolving; Wind tunnel data measurement

 

Presenting Author: Ladan Momayez University of Pittsburgh at Johnstown

Presenting Author Biography: Ladan Momayez is currently an assistant professor at the University of Pittsburgh at Johnstown. She holds a Ph.D. in Thermal and Mechanical Engineering from École Polytechnique de Nantes, France. From 2011 to 2022, she served as a researcher at the Royal Military College of Canada (RMC). Prior to joining RMC, she was an assistant professor (2008-2010) at the Department of Mechanical Engineering and Production, Université de Caen, France. Additionally, she worked as a CNRS Researcher (2007-2008) at Université de Nantes, France.
Her research interests encompass fluid mechanics with a focus on hydrodynamic stability and transition to turbulence, thermo-fluids and aeronautical engineering, convective heat transfer, heat transfer and process intensification, energy efficiency, turbulent flows, and vortex dynamics and their technological applications.

Authors:

Ladan Momayez University of Pittsburgh at Johnstown
Marouen Dghim Université de Sherbrooke
Mohsen Ferchichic Royal Military College of Canada
Farhang Daneshmand Penn State University-Scranton