Installation & Setup Guide

System Requirements

Component	Requirement
OS	Linux (tested on Ubuntu 22.04)
GPU	NVIDIA GPU (Ampere or newer recommended)
CUDA	12.x
Compiler	NVIDIA HPC SDK 24.x or 25.x (`mpif90`)
MPI	OpenMPI bundled with HPC SDK
CMake	3.18 or newer
fypp	any version (`pip install fypp`)
Python	3.10 or newer (optional, for Python API and tests)

1. Install NVIDIA HPC SDK

The solver requires mpif90 from the NVIDIA HPC SDK. Download the installer from:

https://developer.nvidia.com/hpc-sdk

After installation, verify the tools are on your PATH:

mpif90 --version
mpirun --version

2. Install CMake

Most Linux distributions include a recent CMake. If yours does not:

# Ubuntu 22.04+
sudo apt-get install cmake

# Or download from https://cmake.org/download/

Verify:

cmake --version   # must be 3.18 or newer

3. Install fypp

CMake calls fypp to expand the .f90.fypp Fortran templates at build time:

pip install fypp

4. Clone the Repository

git clone https://github.com/htymjun/OUxSBLI.git
cd OUxSBLI

5. Install the Python Package (optional)

Install the ouxsbli Python package and test dependencies:

pip install -e ".[dev]"

This installs: - ouxsbli — the Python API for parametric runs (editable install) - numpy — array operations - vtk — VTK file reading - pytest — for running the test suite

Tip: Use a virtual environment to keep dependencies isolated:
python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

6. Build a Test Case

Each case directory contains a CMakeLists.txt. To build the NS Taylor-Green vortex case:

cd 3D_solver/NSTGV
cmake -B build && cmake --build build -j

CMake runs fypp on all .f90.fypp templates, then compiles with mpif90. The executable a.out lands in build/.

7. Run the Simulation

cd build
mpirun -n 2 ./a.out

VTK output files (Q00000.vtr, Q00001.vtr, …) appear in data/. Open them in ParaView as a time series.

Available Cases

2D Solver (`2D_solver/`)

Directory	Physics	Description
`BL/`	Navier-Stokes	Supersonic laminar boundary layer (M=2)
`DSL/`	Euler	Double shear layer
`EVC/`	Euler	Euler vortex convection (grid-convergence study)
`OS/`	Euler	2D oblique shock (M=2, θ=8°)
`SBLI/`	Navier-Stokes	2D shock-boundary layer interaction
`ST/`	Euler	Sod shock tube

3D Cartesian Solver (`3D_solver/`)

Directory	Physics	Description
`DHIT/`	Navier-Stokes	Decaying homogeneous isotropic turbulence
`ETGV/`	Euler	Entropy-preserving Taylor-Green vortex
`IVST/`	Euler	Inviscid vortex smooth test case
`KHI/`	Euler	Kelvin-Helmholtz instability
`NSTGV/`	Navier-Stokes	NS Taylor-Green vortex (Re=1600, M=1.25)
`SBLI/`	Navier-Stokes	Shock-boundary layer interaction (RESCALE=True)
`STZ/`	Navier-Stokes	z-direction MPI halo exchange validation
`TBL/`	LES	Turbulent boundary layer (Hybrid scheme)

Curvilinear Solver (`3D_solver_curv/`)

Directory	Physics	Description
`NACA/`	Navier-Stokes	NACA 0012 airfoil on an O-grid
`CORN/`	Navier-Stokes	Compression corner (M=2, θ=8°)

Note: The curvilinear solver also uses CMake. Build the same way: cmake -B build && cmake --build build -j

Configuration Reference

Compile-time scheme and physics choices are set in config.fypp, not in mod_globals.f90. See Configuration for details.

At a glance, the dispatch encoding used internally by mod_constant.f90:

Parameter	kind=2	kind=4	kind=8
`id_visc`	Euler	Navier-Stokes	LES
`id_accuracy`	2nd order	4th order	6th order
`id_tvd`	no limiter	tvd	hybrid

`id_scheme`	Type	Scheme
`integer(2)`	KEEP	Kinetic Energy & Entropy Preserving
`real(2)`	SLAU	Simple Low-dissipation AUSM
`real(4)`	Roe	Roe approximate Riemann
`real(8)`	Hybrid	KEEP ↔ SLAU via Ducros sensor

These Fortran parameters are generated automatically from config.fypp — you do not edit them directly.