Declared straight-pipe Darcy evidence
Hydraulic line velocity & loss
Inputs
Steady flow through one constant-ID circular line segment.
Actual internal diameter, not nominal hose or pipe size.
Declared straight length only; fittings, bends, and networks are excluded.
User-entered Darcy friction factor; it is not derived or selected by this workspace.
User-entered density at the stated fluid condition; viscosity and temperature changes are excluded.
A user-stated comparison value; this workspace does not select an acceptable limit.
Results
A wrong number here has physical consequences. Check the method and the boundary below before using this result, and have it reviewed by someone accountable for the design.
Internal flow areaA
201.06
Mean line velocity
2.4868
Declared-fluid Darcy major loss
49.28
Mean velocity / declared reference
62.17
%A = πDi²/4; vmean = Q/A; Δpmajor = f(L/Di)(ρv²/2); comparison = vmean/vref
A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.
Nearby: Hydrostatic pressure · Flow continuity · Pipe mean velocity · Bernoulli equation
Method
Formula, when it applies, and when it does not
Calculate circular line area, mean fluid velocity, and declared-fluid Darcy major loss for one straight line, then compare velocity to a user-reference.
A = πDi²/4; vmean = Q/A; Δpmajor = f(L/Di)(ρv²/2); comparison = vmean/vref
When
- Circular constant-ID straight line
- Steady incompressible flow
- User-entered friction factor and density
- User-stated velocity reference
Don’t
- This calculates mean velocity and a user-factor Darcy major loss in one constant-ID, straight, steady hydraulic line. It does not select hose, tube, or pipe size; prescribe an acceptable velocity or friction factor; calculate Reynolds number, fittings/minor losses, bends, networks, elevation, surge, cavitation, viscosity/temperature variation, pressure rating, routing, hydraulic-system safety, or approval.