Skip to main content
NASA Advanced Supercomputing (NAS) Division World-class modeling, simulation, and supercomputing in support of the NASA mission

Lattice Boltzmann and Navier-Stokes Cartesian CFD Approaches for Airframe Noise Predictions

AMS Seminar Series

Speaker: Michael Barad, Computational Aerosciences Branch, NASA Advanced Supercomputing Division

Presentation

Seminar Slide Deck (PDF-36.1MB)

Abstract

Lattice Boltzmann (LB) and compressible Navier-Stokes (NS) equations based computational fluid dynamics (CFD) approaches are compared for simulating airframe noise. Both LB and NS CFD approaches are implemented within the Launch Ascent and Vehicle Aerodynamics (LAVA) framework. Both schemes utilize the same underlying Cartesian structured mesh paradigm with provision for local adaptive grid refinement and sub-cycling in time. We choose a prototypical massively separated, wake-dominated flow ideally suited for Cartesian-grid based approaches in this study—the partially-dressed, cavity-closed nose landing gear (PDCC-NLG) noise problem from AIAA's Benchmark problems for Airframe Noise Computations (BANC) series of workshops. The relative accuracy and computational efficiency of the two approaches are systematically compared. Detailed comments are made on the potential held by LB to significantly reduce time-to-solution for a desired level of accuracy within the context of modeling airframe noise from first principles.

Biography

Michael Barad is a research scientist in the Computational Aerosciences Branch at NASA Ames Research Center. He received his B.S. from CU-Boulder in 1993, and his M.S. at UC Berkeley in 1997 focusing on computational environmental fluid mechanics. He received his Ph.D. at UC Davis in 2006, where his dissertation was "An Adaptive Cartesian Grid Projection Method for Environmental Flows." During his Ph.D., he was a DOE Computational Science Graduate Fellow, and through this, he conducted his research within the Applied Numerical Algorithms Group at Lawrence Berkeley National Laboratory. From 2006-2009 he was at Stanford's Environmental Fluid Mechanics Laboratory as a NSF Mathematical Sciences Postdoctoral Research Fellow. There, he continued to focus on structured adaptive mesh refinement (AMR) algorithms, and applied them to simulating multiscale nonlinear oceanic internal gravity waves. Barad then came to NASA Ames in 2009 and has been working with Cetin Kiris within the LAVA group where his focus is applications and numerical tools. In LAVA, he has developed a high-order high-performance immersed boundary code for solving unsteady Navier-Stokes equations using adaptively refined structured Cartesian grids, requiring only a water-tight surface triangulation. With the LAVA team he has extended the Cartesian solver using the Lattice Boltzmann method. Using the LAVA solver he has worked on numerous NASA projects, including: the 21st century launch complex at KSC; SLS unsteady loading; NESC Battery simulations; Landing Gear Noise; SOFIA cavity acoustics; Orion launch abort acoustics; and many others. He has published in the Journal of Fluid Mechanics, Journal of Computational Physics, and others. He received the NASA Early Career Achievement Medal in 2014.