💻 Fortran Source Code Library

We currently offer 172 open-source, production-grade Fortran codes for offline testing. Run calculations locally on your own machine, view code structure, read technical explanations, and download compilation packages including sample input files.

Reynolds Number & Entry Length

Core Numerical Engine in Fortran 90 • 23 total downloads

reynolds_number.f90
! Error: Source file reynolds_number.f90 not found on server.

Solver Description

Calculates Reynolds number ($Re = \rho V D_h / \mu$), hydraulic diameter ($D_h$), entry length ($L_e$), and critical velocity ($V_{crit}$) to classify the flow regime.

Key Numerical Methods & Architecture

  • Input Redirection: Reads parameters sequentially from standard input (`stdin`) using Fortran sequential read (`read(*,*)`), ensuring modular integration.
  • Modular Design: Formulated using pure mathematical routines, separation of equations from output formatting, and precise numerical solvers (e.g. bisection, Newton-Raphson).
  • Standard Compliant: Written in clean, standards-compliant Fortran 90 to ensure cross-compiler compatibility.

🛠️ Local Compilation

To test this code on your machine, compile the source code file(s) using a standard Fortran compiler (e.g., `gfortran`).

Compilation Command:

gfortran -O3 reynolds_number.f90 -o reynolds_number

Execution Command:

Execute the program by feeding the sample input file into the program using stdin redirection:

reynolds_number < input.txt

📥 Downloads & Local Files

Preview of the required input file (input.txt):

! Geometry Type (1=Pipe, 2=Plate, 3=Annulus, 4=Duct)
1
! Diameter D or Length L [mm]
50.0
! Outer Diameter [mm] (Annulus only)
0.0
! Width [mm] (Duct only)
0.0
! Height [mm] (Duct only)
0.0
! Velocity V [m/s]
2.0
! Fluid Type (1=Air, 2=Water, 3=Oil, 4=Custom)
2
! Custom Density [kg/m3] (Custom fluid only)
0.0
! Custom Viscosity [Pa-s] (Custom fluid only)
0.0