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1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator

Easily calculate and compute 1d compressible fanno flow (duct friction & choking length) calculator with accurate equations, live formulas, and expert guidance.

Duct inlet Mach number.

Pipe or duct internal diameter.

Skin friction f ≈ 0.003 to 0.008 (Darcy f_D = 4f).

Air γ = 1.40.

Calculated Result
26.5 m

Choking Length (L*)

Choking Length (L*)

26.5 m

Choking Duct Length L Star Meters

26.5

Fanno Parameter4f L Star Over D

5.3

Static Pressure Ratio P Over P Star

3.62

Friction Choking Assessment

Subsonic flow accelerates down duct due to friction until M = 1 at exit (L = L*)

26.5 — m

Calculation Breakdown

  1. Applied FormulaCalculates the maximum adiabatic pipe length L* before wall friction drives compressible flow to sonic choking (M = 1) using Fanno flow theory.\frac{4f L^*}{D} = \frac{1 - M^2}{\gamma M^2} + \frac{\gamma + 1}{2\gamma} \ln\left[ \frac{(\gamma + 1)M^2}{2\left(1 + \frac{\gamma - 1}{2} M^2\right)} \right]

Fanno Flow Friction Choking Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.06.6132027Choking Length (L*)

What Is the 1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator?

This tool computes 1d compressible fanno flow (duct friction & choking length) calculator with high precision arithmetic.

How Does the 1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator Work?

Calculates the maximum adiabatic pipe length L* before wall friction drives compressible flow to sonic choking (M = 1) using Fanno flow theory.

1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

4fL∗D=1−M2γM2+γ+12γln⁡[(γ+1)M22(1+γ−12M2)]\frac{4f L^*}{D} = \frac{1 - M^2}{\gamma M^2} + \frac{\gamma + 1}{2\gamma} \ln\left[ \frac{(\gamma + 1)M^2}{2\left(1 + \frac{\gamma - 1}{2} M^2\right)} \right]

Calculates the maximum adiabatic pipe length L* before wall friction drives compressible flow to sonic choking (M = 1) using Fanno flow theory.

How to Use the 1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator

  1. Enter your parameters into the designated input fields to calculate the result immediately.

Step-by-Step Example Calculation

1D Compressible Fanno Flow (Duct Friction & Choking Length) Calculator Example

Input Values:

inletMachNumberM1:0.3
ductHydraulicDiameterMeters:0.1
fanningFrictionFactorF:0.005
ratioOfSpecificHeatsGamma:1.4
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required m.

Factors That Affect the Result

  • Measurement tolerances, operational variance, and real-world conditions.

When Should You Use This Calculator?

  • Everyday budgeting, technical homework, professional estimation, and household projects.

Assumptions & Limitations

  • Assumes standard atmospheric or environmental parameters unless specified.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Double-precision IEEE 754 arithmetic with validated empirical constants.

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