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Numerical Modeling Of Separated Flows At Moderate Reynolds Numbers Appropriate For Turbine Blades And Unmanned Aero Vehicles

Event Type: 
Date and Time: 
Friday, July 31, 2015 - 16:00
CTR Conference Room 103
Event Sponsor: 
Parviz Moin, Director of Center for Turbulence Research
Dr. Giacomo Castiglioni, Aerospace Engineering, University of Southern California

Flows over airfoils and blades in rotating machinery, for unmanned and micro-aerial vehicles, wind turbines, and propellers consist of a laminar boundary layer near the leading edge that is often followed by a laminar separation bubble and transition to turbulence further downstream. Typical Reynolds averaged Navier-Stokes turbulence models are inadequate for such flows. Direct numerical simulation is the most reliable, but is also the most computationally expensive alternative. This work assesses the capability of immersed boundary methods and large eddy simulations to reduce the computational requirements for such flows and still provide high quality results.

Two-dimensional and three-dimensional simulations of a laminar separation bubble on a NACA-0012 airfoil at Re_c = 50,000  at 5 degree of incidence have been performed with an immersed boundary code and a commercial code using body fitted grids. Several sub-grid scale models have been implemented in both codes and their performance evaluated.

The numerical dissipation inhibits the predictive capabilities of large eddy simulations whenever it is of the same order of magnitude or larger than the sub-grid scale dissipation. A particular emphasis is given to the quantification of the numerical dissipation in the commercial code.

Dr. Giacomo Castiglioni graduated with a Bachelor of Science in Mechanical Engineering from the Polytechnic University of Milan (Italy) in 2009, and received his Master of Science in Aerospace Engineering form the University of Southern California in 2011. In 2010 he joined the group of Professor Domaradzki at the University of Southern California where he graduated with a PhD in Aerospace Engineering in 2015. During 2011 and 2013 he attended the SFB-TRR40 summer program at the Technical University of Munich, Germany. His research interests include turbulence modeling and high-order unstructured solvers.