Formulation and Implementation of Inflow/Outflow Boundary Conditions to Simulate Propulsive Effects Model

Speaker: David Rodriguez, Science and Technology Corporation, NASA Ames Research Center
May 10, 2018

Presentation

Abstract

Boundary conditions appropriate for simulating flow entering or exiting the computational domain to mimic propulsion effects have been implemented in an adaptive Cartesian simulation package. A robust iterative algorithm to control mass flow rate through an outflow boundary surface is presented, along with a formulation to explicitly specify mass flow rate through an inflow boundary surface. The boundary conditions have been applied within a mesh adaptation framework based on the method of adjoint-weighted residuals. This allows for proper adaptive mesh refinement when modeling propulsion systems. The new boundary conditions are demonstrated on several notional propulsion systems operating in flow regimes ranging from low subsonic to hypersonic. The examples show that the prescribed boundary state is more properly imposed as the mesh is refined. The mass-flow-rate steering algorithm is shown to be an efficient approach in each example. To demonstrate the boundary conditions on a realistic complex aircraft geometry, two of the new boundary conditions are also applied to a modern low-boom supersonic demonstrator design with multiple flow inlets and outlets.

Biography

David Rodriguez earned his Ph.D. from Stanford University in 2001 where his work focused on applying multidisciplinary optimization techniques to revolutionary aircraft designs. Since then he has worked at NASA Ames and a small startup in Palo Alto developing tools for designing supersonic business jet aircraft. For the past 5 years, David has been working at NASA Ames for Science & Technology Corporation in the Cart3D Development Group. His current work focuses on extending the Cart3D design framework to aerostructural problems and developing an integrated boundary layer method for the Cart3D Euler solver.

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