Investigation of unsteady secondary flows and turbulence in heterogeneous TBLs | Dr. D. Wangsawijaya

#Aeroseminar #TUDelft #Aerodynamics
The Aeroseminar lecture given by Dr. D Wangsawijaya titled "Coherent structures in turbulent wakes" in the faculty of Aerospace Engineering at TU Delft.
Abstract
The nature of wall-bounded turbulent flows over rough surfaces, whose roughness distribution is homogeneous, has been studied extensively and is relatively well defined. Most surfaces in nature and engineering applications, however, are heterogeneous and the heterogeneity can be arranged in an infinite number of ways. Examples include: rivets on aircraft, bio-fouling on ships, sedimentation on riverbeds, and forest and crop boundaries in the atmospheric surface layer. This talk will focus on a specific heterogeneous surface roughness composed of spanwise-alternating smooth and rough strips. Embedded within the turbulent boundary layer developing over such surface are secondary flows in the form of counter-rotating streamwise vortices. Instantaneously, these secondary flows are visually similar to the large-scale motions (LSMS/VLSMs) that occur naturally over smooth walls - both appear as elongated high- and low-momentum streaks. In this talk, I will investigate parameters affecting the formation of the secondary flows and take a closer look at the structures of turbulence in roughness-induced secondary flows, and how these structures compare to the naturally occurring LSMS/VLSMS.
Biography
Dr. Dea Wangsawijaya is a postdoctoral research fellow at the University of Southampton. She obtained her PhD in Mechanical Engineering from the University of Melbourne in 2021. Previously, she attended Institut Teknologi Bandung, Indonesia, where she obtained MSc and BSc in Aeronautics and Astronautics. Her research interests lie in the experimental investigation of turbulent flows, especially those developing over canopies and surface roughness.