Fluid Network Studio

Verification

Fluid Network Studio is built to be auditable. Every result on this page is produced by the same solver the app runs, then compared against an independent reference: a recognised closed-form solution, a published textbook benchmark, or the independent OWA-EPANET 2.2 engine. Nothing is tuned to match a target; an automated test re-runs every case on each build, so this page can never drift from what actually passes; and every solve reports its mass- and energy-conservation residuals. Across all 11 cases the largest deviation from its independent reference is 0.32%.

  • Solved live by the real solver
  • Nothing tuned to a target
  • Cross-checked against OWA-EPANET 2.2
  • Drift-guarded by the test suite
  • Conservation residuals on every solve

Independent cross-check against EPANET

  • Looped network vs OWA-EPANET 2.2

    Reference: the independent, public-domain OWA-EPANET 2.2 engine

    Reference45.783 L/s
    Studio (Flow (a loop branch))45.783 L/s
    Deviation< 0.01%
    Tolerance0.1%

    A five-pipe looped network solved by both engines from identical inputs. All five pipe flows agree with OWA-EPANET 2.2 to within about 0.003% - independent-engine agreement, the strongest check we run.

    Explore a related example in the Studio

Published benchmark

  • Three-reservoir junction (Darcy-Weisbach)

    Reference: Larock, Jeppson & Watters, Hydraulics of Pipeline Systems (three-reservoir junction); independent reference solver

    Reference31.212 m
    Studio (Junction head)31.212 m
    Deviation< 0.01%
    Tolerance0.1%

    The classic textbook problem: three reservoirs at 40, 28 and 15 m feed a common junction; the middle reservoir correctly receives flow. Verifies the junction mass balance and the flow-direction signs.

    Explore a related example in the Studio

Liquid networks

  • Single pipe, turbulent (vs Colebrook-White)

    Reference: Colebrook-White equation (the classical implicit turbulent friction law)

    Reference20.144 L/s
    Studio (Flow)20.210 L/s
    Deviation0.32%
    Tolerance0.5%

    FNS uses the explicit Churchill (1977) correlation, which agrees with Colebrook-White in the turbulent range to a fraction of a percent.

  • Laminar line (Hagen-Poiseuille, exact)

    Reference: Hagen-Poiseuille law (exact, laminar flow)

    Reference0.0339 L/s
    Studio (Flow)0.0339 L/s
    Deviation< 0.01%
    Tolerance0.1%

    Churchill reduces exactly to the laminar f = 64/Re below Re = 2000, matching the analytic solution.

Pumps

  • Pump + system operating point

    Reference: Least-squares pump curve at the system operating point; independent reference solver

    Reference17.817 L/s
    Studio (Pump flow)17.817 L/s
    Deviation< 0.01%
    Tolerance0.2%

    A pump feeding two parallel branches. The solver finds the operating point where the fitted pump curve (here exactly H = 25 - 8000 Q^2) meets the system curve.

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Hazen-Williams

  • Single pipe, Hazen-Williams (closed form)

    Reference: EPANET 2 Users Manual (Rossman 2000), Hazen-Williams head-loss, SI form

    Reference184.54 L/s
    Studio (Flow)184.54 L/s
    Deviation< 0.01%
    Tolerance0.2%

    hf = 10.674 L Q^1.852 / (C^1.852 D^4.871), C = 130. The solver, the closed form and EPANET's native Hazen-Williams all use this constant.

    Explore a related example in the Studio

  • Three-reservoir junction, Hazen-Williams

    Reference: qa Part L junction root-find; cross-checked against OWA-EPANET 2.2 native Hazen-Williams

    Reference81.668 m
    Studio (Junction head)81.668 m
    Deviation< 0.01%
    Tolerance0.02%

    Three reservoirs (100, 80, 40 m) to a common junction; verifies junction mass balance and flow-direction signs under Hazen-Williams.

    Explore a related example in the Studio

Compressible gas

  • Isothermal gas pipeline pressure drop

    Reference: Exact isothermal compressible relation incl. the acceleration term (Saad, Compressible Fluid Flow)

    Reference1.165 kg/s
    Studio (Mass flow)1.162 kg/s
    Deviation0.24%
    Tolerance0.5%

    Air from 600 to 400 kPa absolute down a 200 m line: a 33% density fall. The gas kernel solves in pressure-squared with the exact isothermal relation; density falls and velocity climbs toward the outlet.

    Explore a related example in the Studio

Heat transfer

  • Insulated hot-water main, delivered temperature

    Reference: Gnielinski film + composite-cylinder resistance (Incropera, Fundamentals of Heat and Mass Transfer); independent reference solver

    Reference69.643 °C
    Studio (Delivered temperature)69.643 °C
    Deviation< 0.01%
    Tolerance0.1%

    A 70 °C main, 200 m of DN100 with 30 mm of insulation, ambient 15 °C. The coupled thermal-hydraulic solve builds the per-metre U from an inner film, the steel wall and the lagging.

    Explore a related example in the Studio

Non-Newtonian

  • Three-reservoir junction, power-law fluid

    Reference: Metzner-Reed (1955) generalised Reynolds number + Dodge-Metzner (1959) friction; independent reference solver

    Reference31.792 m
    Studio (Junction head)31.792 m
    Deviation< 0.01%
    Tolerance0.1%

    A shear-thinning power-law fluid (K = 0.5, n = 0.5) in a three-reservoir junction. Each pipe picks its regime from the generalised Reynolds number; two run turbulent, one laminar.

    Open this exact case in the Studio

Other methods

  • Single pipe, fixed friction factor (closed form)

    Reference: Darcy-Weisbach with a constant f (exact)

    Reference133.15 L/s
    Studio (Flow)133.15 L/s
    Deviation< 0.01%
    Tolerance0.2%

    hf = f (L/D) V^2/2g, f = 0.02. Reproduces textbook examples stated at a fixed friction factor.

What Fluid Network Studio does not model, and why

Stating the boundaries plainly is part of being trustworthy. These are deliberate fences, not gaps - each belongs to a specialist tool:

  • Transient / surge / water hammer. Fluid Network Studio is steady-state (with an extended-period, quasi-steady mode); pump-trip and valve-closure pressure transients belong in a dedicated surge package.
  • Settling and heterogeneous slurries. Non-Newtonian support is for homogeneous power-law and Bingham-plastic fluids only; deposition velocities and two-phase transport are out of scope.
  • Relief-valve and pressure-control sizing. Control-valve logic, PRV/PSV networks and relief sizing are the domain of specialist suites.
  • Joule-Thomson and gas mixtures. The gas solver handles single-component compressible flow; multi-component mixtures and Joule-Thomson effects are not modelled.

Where the steady network needs full 3-D detail at a component, the CFD-coupling export links the verified network solver to a STAR-CCM+ model - a differentiator no spreadsheet or standalone desktop package offers.

Like any analysis tool, Fluid Network Studio supports a qualified engineer's judgement rather than replacing it; results should be reviewed before they are relied upon. See how it works for the methods, or open the Studio and check a network you already know the answer to.