Reynolds Number & Entry Length

Standalone, self-contained numerical routine. Verify algorithms, inspect boundary condition equations, or compile locally for batch parametric runs.

📦 Download Complete ZIP 📥 Download .f90 Code 📄 Download input.txt

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Solver Purpose & Physical Scope

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.

📂 Discipline: Fluid ⚡ Precision: IEEE-754 64-bit Real(`real(8)`) 📥 Total Downloads: 596 times 📄 Source File: reynolds_number.f90

📁 calcul/Tools / reynolds_number.f90

! =========================================================================
! Source File: reynolds_number.f90 (calcul/calcul/Tools)
! =========================================================================

! [Fortran 90/2008 Double-Precision Solver]
! Ready for offline compilation with gfortran.

💻 How to Compile & Run Locally

1. Compilation (GNU Fortran / Intel oneAPI):

gfortran -O3 reynolds_number.f90 -o reynolds_number

2. Execution with input.txt redirection:

reynolds_number < input.txt

📄 Sample input.txt File Structure

Sample Data:

1
50.0
0.0
0.0
0.0
2.0
2
0.0
0.0

Parameter Description:

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