3301 South Dearborn Street
Chicago, IL 60616
Armour College of Engineering's Mechanical, Materials & Aerospace Engineering Department will welcome Mr. Alvaro Vidal, PhD candidate in the Mechanical, Materials, and Aerospace Engineering Department, to present his lecture, Secondary Flow in Moderately Complex Geometries.
Direct numerical simulations (DNSs) of fully-developed turbulent flow through ducts with different cross-sectional geometries are performed to characterize the secondary flow and its influence on the turbulence statistics. The role of streamwise corners in the production of secondary flows is evaluated by analyzing square ducts with rounded corners, rectangular ducts with semi-cylindrical sidewalls and spanwise-periodic channels with in-phase sinusoidal walls. Unexpectedly, the magnitude of the mean cross-flow in ducts with rounded corners and sidewalls is similar to the corresponding cases with sharp corners. However, the secondary vortices relocate close to the region of wall-curvature transition. The sinusoidal wall geometry creates an alternating pattern of internal and external corners of different angles and sizes. The effect of the corner size and angle is analyzed with goal of finding cross-flow distributions that can be replicated at higher Reynolds numbers and to further characterize the multi-scale nature of the secondary flow. The mechanisms that generate the secondary flow are analyzed in terms of the Reynolds-stress tensor using quadrant analysis and conditional averaging to identify the preferential behavior of the bursting events. Implications on design of experimental facilities are briefly discussed.
Alvaro Vidal received his Engineer's Degree in Industrial Engineering and in Industrial Organization Engineering from the University of the Basque Country (Spain), holds an MS in Mechanical and Aerospace Engineering from the Illinois Institute of Technology (USA) and is currently a PhD candidate in the same major under the supervision of Prof. Hassan Nagib. His research is focused on the analysis of wall-bounded turbulent flows using high-order spectral direct numerical and simulations.