An orthonormal basis set is introduced for use in generating global solutions to nonlinear differential equations with shocks. By global, it is meant that a single series solution is generated that is valid over the entire domain, not a separate solution...

Over the past several decades, one class of problems in computational fluid dynamics (CFD) that has undergone substantial development involves movement of the fluid domain boundary. The problem class exists when the fluid domain boundary is either explicitly time-dependent, or is known a priori and...

ARC2D is a computational fluid dynamics (CFD) program for two-dimensional airfoil and simply connected geometries. The program uses implicit finite-difference techniques to solve two-dimensional Euler equations and Navier-Stokes equations. It is based on the Beam and Warning...

Pegasus software is used as a pre-processor for overset-grid Computational Fluid Dynamics (CFD) simulations. It provides the hole-cutting and connectivity information between structured overset grids. The main features of the software include automated hole-cutting algorithms, a...

PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools that...

This innovation addresses several critical issues in the construction of cut control volumes using embedded-boundary Cartesian mesh generators. The innovation considers the case of a surface triangulation intersecting the face of a Cartesian hex...

Aerodynamic heating of aerospace vehicles such as aircraft and spacecraft occurs when air passes over a vehicle during transit, ascent, descent, and re-entry, and is a function of re-entry angle, speed, air density, thermal protection system material, and vehicle configuration. The degree of aerodynamic...

Fuel slosh is excited during spacecraft maneuvers. The forces and torques exerted on the spacecraft by the slosh must be controlled by the attitude control system to maintain correct pointing and spacecraft orbit. In some rare cases, the attitude control system may excite the slosh...

This work extends the mesh generation capability of NASA’s Cart3D flow simulation software package to permit cell-by-cell mesh enrichment. Cart3D allows users to perform automated Computational Fluid Dynamics (CFD) analysis on a complex geometry. It includes utilities for...

Reynolds-averaged Navier-Stokes (RANS) Integration for Shock- Noise (RISN) is a computer program that evaluates acoustic analogies to predict jet noise. Jet noise is due to turbulence from the chaotic flow within the exhaust of a rocket or air-breathing jet engine. The source of jet...

This suite of computer programs, called “tools,” is used to calculate local flow angles over damage sites in the Shuttle Orbiter Thermal Protection System (TPS). It provides a quick and easy way to compute cross flow angles over points of interest on the Shuttle Orbiter TPS.

The Reacting Flow Environments branch at NASA ARC is interested in characterizing the aerothermal environment of three main classes of problem: planetary entry vehicles, reusable launch vehicles (RLVs), and arc-jet (or other ground test) flow simulations. Each of these problem classes has...

This invention relates to a fluid film bearing and a process for evaluating pneumatic hammer instability. Based on the stability criteria, a method was developed using 3D CFD (computational fluid dynamics) evaluation dynamics to evaluate the onset of pneumatic...

When designing aerodynamic structures, it is important to understand if, and under what aerodynamic conditions, the structure will be stable and unstable. This is especially true if a structure is inherently flexible, such as a wing, where unstable response leads to oscillations of the...