Resonant Mode Control from Transonic to Hypersonic Boundary Layers Over Complex Wall Impedance

Speaker: Carlo Scalo, Dept. of Mechanical Engineering, Purdue University
August 7, 2017

Presentation

Abstract

The talk will discuss fundamental computational and physical aspects associated with transitional and turbulent boundary layer control over porous walls. The dynamics of waves propagating in the porous cavities will be analyzed via a novel inverse acoustic eigenvalue approach (Patel and Scalo, 2017) with focus on the characterization of the complex broadband surface impedance. Results from high-fidelity numerical simulations retaining full aeroacoustic coupling between the overlying flow and porous walls via imposition of time-domain impedance boundary conditions, or TD-IBC (Scalo et al, 2015-2016), will be presented. Flow conditions investigated include subsonic-to-transonic compressible channel flow turbulent, flow over a NACA 4412 airfoil in pre-stalled conditions and a hypersonic transitional boundary layer over a 7-degree wedge. It is shown how porous walls can be used to improve the aerodynamic performance of lifting surfaces by delaying boundary layer separation or high-speed vehicles by attenuating ultrasonic waves responsible for transition to turbulence.

Biography

Carlo Scalo is an Assistant Professor in the School of Mechanical Engineering at Purdue University. He completed his postdoctoral appointment (2014) at the Center for Turbulence Research at Stanford University working on theoretical and numerical modeling of thermoacoustic devices and sound-turbulence interaction in compressible boundary layers. Prior to that, he obtained his Ph.D. (2012) from Queen's University, Canada, working on subgrid-scale modeling of high-Schmidt-number turbulent mass transfer in equilibrium and non-equilibrium geophysical flows. He obtained his B.Eng. (2006) and M.Sc. (2008) degrees in Aerospace Engineering at the Universita' degli Studi di Napoli - Federico II, Italy. Scalo currently holds research grants with AFOSR, NSF, NAVAIR, Ford Motor Company, and Rolls Royce on topics including (but not limited) to thermo-acoustics, nonlinear acoustics, numerical methods for acoustics in complex geometries, low- and high-speed turbulent boundary layers, turbulent mixing and heat-and-mass transfer, and subgrid-scale modeling of vortex dominated flows.

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