LNS3D compressible Navier-Stokes Solver

LNS3D is part of the Flow Physics & Simulation code suite of fluid mechanics analysis codes to explore linear and nonlinear phenomena, primarily for compressible flows..

The main LNS3D web-site describes the overall capability and there are numerous README.md files (including this one) that describe specific capabilities, codes, and test cases.

Background

LNS3D solves the compressible Navier-Stokes equations with 3-components (u,v,w) and 2.5 dimensions (x,y,z) were the solution must be a single Fourier mode.

LNS3d uses a fourth-order finite-difference method and is generally designed to resolve highly sensitive flow phenomena such as aero-acoustics, receptivity and linear instability.

LNS3D can also solve both linear and nonlinear 2.5d-3c problems depending on the problem setup but the code is specifically designed to solve for perturbations on a baseflow to increase the fidelity of the solution.

Building

To build you need to link (and possibly edit) the most appropriate *.mak file. For example, using GCC Gfortran on Mac OS X (Darwin), one would use

cd src
ln -s gcc.mak Makefile

And then

make clean && make

The executable is lns3d.

Auxiliary Tools

The following tables describes the supporting tools for lns3d that are required for complete end-to-end workflows and analysis.

Directory	Description
src	Primary source for lns3d flow solver
ssd	Original Cray SSD enabled source for lns3d flow solver
nossd	Original Cray version of lns3d flow solver with SSD disabled
pre	Preprocessor that makes consistent metrics from a grid file
util	Various utilities for preparing and analyzing lns3d runs
mesh	Mesh generators for specific types of geometries
test	Simple tests and examples of lns3d and tools
docs	Documentation information

Each of these tool directories contains a separate README file that describes how to build and use them.

Finally, the test directory contines several examples demonstrating workflows and capabilities of lns3d that can both help assess that your build are working correctly and show new users how to setup and run problems.

Example Calculation

Compressible vortex rebound from a solid wall

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S. Scott Collis
flow.physics.simulation@gmail.com