Free · Physics models
Ideal Flow Pressure Between Two Points
Relate pressure, elevation, speed and circular-pipe flow along an ideal fluid streamline.
- Formula & worked example
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Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
Volumetric flow rate = 0.0078539816; Mass flow rate = 7.8539816; Pipe diameter at position 2 = 7.0710678. The worked example lists its inputs and unit conventions.
p + ρv²/2 + ρgh = constant; Q = πd²v/4; ṁ = ρQ.
Worked example
Enter these known values and leave the other values blank.
- Fluid density
- 1000 kg/m³
- Pressure
- 200000 Pa
- Height
- 2 m
- Height
- 1 m
- Fluid speed
- 1 m/s
- Fluid speed
- 2 m/s
- Pipe diameter at position 1
- 10 cm
- Pressure
- 208307 Pa
- Pressure change
- 8307 Pa
- Pipe diameter at position 2
- 7.071 cm
- Volumetric flow rate
- 0.007854 m³ / sec
- Mass flow rate
- 7.854 kg / sec
Assumptions and limitations
- Steady incompressible inviscid flow along one streamline with no pumps or friction losses is assumed. The supported captured branch uses positive heights referenced to a datum below both points, positive pressures and speed magnitudes.
- Clear the quantity to solve an inverse; keep known quantities fixed with locks. Some inverses are singular or ambiguous and require further known values.
- Unit selectors convert the same physical quantity. Rounded reference constants and presets limit physical accuracy even when arithmetic displays more digits.
Common questions
What does this model assume?
Steady incompressible inviscid flow along one streamline with no pumps or friction losses is assumed. The supported captured branch uses positive heights referenced to a datum below both points, positive pressures and speed magnitudes.
Can I solve for an input?
Editable calculated fields support the captured inverse relationships. Clear the unknown and supply enough independent known values; an inverse must remain within the declared physical domain.
References
Steady incompressible inviscid flow along one streamline with no pumps or friction losses is assumed. The supported captured branch uses positive heights referenced to a datum below both points, positive pressures and speed magnitudes.