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Design and Analysis Software

A variety of software is used in the development of inlets and nozzles.  This includes:

Inlet Software

SUPIN – Supersonic Inlet Design Code

SUPIN is used to design and analyze the aerodynamic performance of supersonic inlets. This includes axisymmetric pitot, three-dimensional pitot, axisymmetric outward-turning, two-dimensional single-duct, two-dimensional bifurcated-duct, and streamline-traced inlets.  It combines the functionality of the older inlet codes listed below into a more up-to-date software package.

SUPIN reads a text data file containing input factors that describe the inlet geometry, design parameters, and flow conditions.  It generates the geometry of the inlet and performs some design of the inlet configuration.  Lastly, it calculates the aerodynamic performance in terms of the inlet flow rates, total pressure recovery, and drag.

The low-fidelity aerodynamic analysis and design methods are based on analytic, empirical, and numerical methods that provide for quick design and analysis. SUPIN generates inlet geometry in the form of coordinates, surface angles, and cross-sectional areas. It can also generate inlet surface grids and three-dimensional, structured volume grids for use with higher-fidelity computational fluid dynamics (CFD) analysis.

PINDAP – Planar Inlet Design and Analysis Process

PINDAP is a collection of software tools that allow the efficient aerodynamic design and analysis of planar (two-dimensional and axisymmetric) inlets. Inputs support parametric inlet design to efficiently model the geometry and generate the grid for CFD analysis with design changes to those parameters. The aerodynamic analysis is performed by spawning processes to the Wind-US computational fluid dynamics (CFD) program. PINDAP can be used for subsonic, supersonic, and hypersonic inlets.

IPAC – Inlet Performance Analysis Code

IPAC embodies a series of one-dimensional analyses that have been developed to predict the performance of a given inlet geometric design.  A text input data file specifies the geometric description of a pitot, two-dimensional, or axisymmetric-spike inlet along with flow conditions.

Outputs include the inlet weight flow, total pressure recovery, and aerodynamic drag coefficient for the specified inlet geometric design. The calculated inlet performance parameters may be used in preliminary inlet design studies, subsequent engine cycle analyses, or installed engine performance calculations for existing uninstalled engine data.


LAPIN solves the quasi-one-dimensional Euler equations in a time-accurate manner to solve for unsteady flow within a supersonic mixed-compression inlet.  It was intended to simulate unsteady shock motion.

LERCINLT – Lewis Research Center Inlet Design Code

LERCINLT is a classic inlet design code that uses the method of characteristics.  It can be used to design external and internal supersonic diffuser profiles of two-dimensional and axisymmetric-spike mixed-compression inlets.

The program inputs are formulated to represent the desired engineering design parameters, such as throat Mach number and flow angle. The characteristic equations are used to locate points in physical space where the flow properties change. The compatibility conditions are used to determine the flow properties.

INLETMOC – Inlet Method of Characteristics

INLETMOC computes supersonic flow about and within two-dimensional and axisymmetric-spike mixed-compression inlets using the method-of-characteristics.

Nozzle Software

NPAC – Nozzle Performance Analysis Code

NPAC is a simple and accurate nozzle performance analysis methodology.  The geometry modeling requirements are minimal and very flexible, thus allowing rapid design evaluations. The solution techniques accurately couple: continuity, momentum, energy, state, and other relations that permit fast and accurate calculations of nozzle gross thrust.

The control volume and internal flow analyses can account for the effects of over/under expansion, flow divergence, wall friction, heat transfer, and mass addition/loss across surfaces. The nozzle performance methodology results are in excellent agreement with experimental data for various nozzle designs over a range of operating conditions.

Rao Nozzle Design Code

The Rao code is an optimum nozzle design code.

MOC/STT – Method of Characteristics/Streamline Tracing Tool

The MOC/SST software is a 2D and 3D Method of Characteristic (MOC) tool for designing complex nozzle geometries. These tools are GUI driven and designed for Windows-based platforms.  This software was developed under contract with the Applied Physics Laboratory at John Hopkins University.

Reynolds-Averaged Navier-Stokes (RANS) Software

FUN3D – Fully Unstructured Three Dimensions

FUN3D uses a node-based finite-volume discretization to obtain solutions on mixed-element unstructured grids.  It has a variety of thermodynamics and turbulence models, as well as boundary conditions for internal flows and propulsion simulations.  It supports Chimera overset grids, automatic domain decomposition, and adjoint- and feature-based grid adaptation.

Cart3D – Cartesian Three Dimensions

Cart3D is a high-fidelity inviscid analysis package for conceptual and preliminary aerodynamic design. It allows users to perform automated CFD analysis on complex geometry and supports steady and time-dependent simulations. Cart3D uses an embedded multilevel Cartesian mesh to discretize the space surrounding the geometry and determines the surface geometry out of the set of “cut-cells” which intersect the surface.  The package features fully-integrated adjoint-driven mesh adaptation and also includes utilities for geometry import, surface modeling and intersection, mesh generation, and post-processing of results.  At GRC, Cart3D has primarily been used for sonic boom calculations.

Large-Eddy Simulation (LES) Software

GFR – Glenn Flux Reconstruction

GFR is a high-order computational fluid dynamics (CFD) code for large-eddy simulations.  It is based on the simple and efficient flux reconstruction method.

Solution variables within each grid cell are represented by a user-selected polynomial of degree P.  Solution points are added within the volume of each cell to resolve this polynomial.  Similar to Discontinuous Galerkin methods, the solution may be discontinuous across cell boundaries.  Arbitrary higher-order accuracy can be obtained by increasing P.  GFR currently supports unstructured grids containing quadrilateral and hexahedra elements.  Extension to other cell topologies is in development.

WRLES – Wave Resolving Large-Eddy Simulation

WRLES uses high-order accurate and high-resolution numerical methods to minimize solution error and maximize the resolution of turbulent structures. Spatial discretization is performed using explicit central differencing. The central differencing schemes in the code include 2nd- to 12th-order standard central difference methods as well as 7-, 9-, 11- and 13-point dispersion relation preserving schemes. Structured multi-block grids with point-matched overlaps are required.

Solution filtering and high-order shock-capturing are included for stability. Time discretization is performed using multistage Runge-Kutta methods that are up to 4th order accurate. Several options are available to model turbulence, including Baldwin-Lomax and Spalart-Allmaras Reynolds-Averaged Navier-Stokes turbulence models, and Smagorinsky, Dynamic Smagorinsky, and Vreman sub-grid scale models for LES.

The code is used to both analyze propulsion system components and test improved LES algorithms (numerical schemes, filters, and sub-grid models).

FDL3DI – Flight Dynamics Laboratory Three-Dimensional Implicit

FDL3DI is a high-order accurate structured grid solver with Chimera overset grid capability.  It is developed by the Air Force Research Laboratory at Wright-Patterson Air Force Base.


Wind-US is a product of the NPARC Alliance, a partnership between the NASA Glenn Research Center (GRC) and the USAF Arnold Engineering Development Center (AEDC)  dedicated to the establishment of a national, applications-oriented flow simulation capability. The Boeing Company  has also been closely associated with the Alliance since its inception, and represents the interests of the NPARC User’s Association.

Wind-US solves the Euler and Navier-Stokes equations of fluid mechanics using multi-zone structured, unstructured, or hybrid grids, along with additional equation sets governing turbulent and chemically reacting flows.

Wind-US Features

Geometric Modeling

Physical Modeling

Solution Algorithms

Parallel Operation


Documentation & Validation

Wind-US Documentation

Detailed information about Wind-US is available at the Wind-US Documentation web site. In addition to the documentation for Wind-US itself, documentation is also available for various pre- and post-processing programs used with Wind-US. Most of the documentation is available in both PDF and HTML form.

Wind-US Validation

There is also a detailed CFD Code Validation web site for Wind-US. The site’s objectives are: (1) to provide documented validation and example cases, with downloadable input and output files, for Wind-US; and (2) to provide analytical, computational, and experimental validation data for use by the CFD community in general.

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