Papers & Reports 2012

Faster networks are continually being built to accommodate larger data transfers. While it is intuitive to think that implementing faster networks will result in higher throughput rates, this is often not the case.
Flow Analysis Tool Whitepaper,NAS Technical Report, March 2012, NASA Ames Research Center, Moffett Field, CA.

The D8 "double-bubble" aircraft is a radical new design that may substantially reduce the fuel burn, noise, and emission of future commercial transportation aircraft. To independently verify some of the advantages proposed in this design, a study of the external aerodynamics of an unpowered version of the D8 aircraft is performed using Overflow.
External Aerodynamics Simulations for the MIT D8 "Double-Bubble" Aircraft Design,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

Time-dependent Navier-Stokes simulations have been carried out for a rigid V22 rotor in hover, and a flexible UH-60A rotor in forward flight.
Advances in Rotor Performance and Turbulent Wake Simulation using DES and Adaptive Mesh Refinement,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

Detached-eddy simulation (DES) based on the v2-f Reynolds-averaged Navier-Stokes (RANS) model is developed and tested. Simulations indicate that this model represents the turbulent wake nearly as accurately as the dynamic Smagorinsky model.
Detached-Eddy Simulation Based on the v²-f Model,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

We present a method for constructing design-appropriate shape parameterizations of discrete surfaces for optimization of flight vehicles. This work is an important step towards our broader goal of offering aerospace designers more relevant, customized control over shape deformation.
Constraint-based Shape Parameterization for Aerodynamic DesignICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

A pressure rail concept for wind tunnel sonic boom measurement of aircraft was manually designed and evaluated with an adjoint-based adaptive Cartesian grid method and validated in various wind tunnel tests.
Design and Evaluation of a Pressure Rail for Sonic Boom Measurement in Wind Tunnels,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

A hybrid grid approach has been developed for the simulation of next generation heavy-lift space vehicles in the launch environment. The motivation for the hybrid method is to reduce the turn-around time of computational fluid dynamic simulations and improve the ability to handle complex geometry and flow physics. Emphasis is placed on understanding and characterizing the effects of high-order spatial differencing, grid resolution, and Spalart-Allmaras detached eddy simulation in predicting the rotor figure of merit and resolving the turbulent rotor wake.
Towards Hybrid Grid CFD Simulations of the Launch Environment ,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

In this paper we present the results of the analytical and numerical studies of the plume interaction with the base flow in the presence of base out-gassing.
Overheating Anomalies during Flight Test due to the Base Bleeding,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

A study on the effect of inflow turbulence boundary conditions on the local flow on and around a body in flight has been carried out. The study has been carried out using OVERFLOW2 flow solver using the default Spalart-Allmaras turbulence model in OVERFLOW.
Effect of Inflow Boundary Conditions on Hovering Tilt-Rotor Flows,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

The goal of this paper is to relate numerical dissipations that are inherited in a selected set of high order shock-capturing schemes with the onset of wrong propagation speed of discontinuities as a function of stiffness of the source term and the grid spacing.
Numerical Dissipation and Wrong Propagation Speed of Discontinuities For Stiff Source Terms,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

The goal of this paper is to relate numerical dissipations that are inherited in a selected set of high order shock-capturing schemes with the onset of wrong propagation speed of discontinuities as a function of stiffness of the source term and the grid spacing.
Advances in Domain Connectivity for Overset Grids Using X-Rays Approach,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

Fully coupled simulations of hydrodynamics and radiative transfer are essential to a number of fields ranging from astrophysics to engineering applications. Results are shown for a number of idealized test problems.
Improved Finite-Volume Method for Radiative Hydrodynamics,ICCFD7 Conference, Big Island, Hawaii, July 9-13, 2012.

More than 25% of NAS/HECC users participated in a user survey in 2011. This report provides a summary of the survey results and related activities to improve performance in several key areas: mass storage and networking, website and documentation, training, and data analysis and visualization.
2011 NAS User Survey Results,Read More