Lab · Fluid Mechanics
Hydrostatics Lab
One fluid at rest, seen four ways. The same density, the same free surface and the same stated pressure reference drive the pressure field, the multi-fluid pressure path, the loading on a submerged plate and the buoyancy on a displaced body — so no two views of this scene can disagree.
The fluid
Gauge pressure is measured relative to the ambient pressure, so 0 kPa means ambient. It may legitimately be negative. No atmospheric pressure is added anywhere in this calculation.
Depth
h is depth below the free surface, positive downward, so a larger h means a higher pressure. z is elevation above the datum, positive upward. They are different quantities and are never mixed.
Pressure field
Pressure at h = 5 m (gauge)
| Free-surface pressure | 0 Pa |
|---|---|
| Hydrostatic rise ρgh | 49.0333 kPa |
| Head of this fluid | 5 m |
Pressure rises linearly with depth, reaching 49.0333 kPa at 5 m.
What this Lab models
A single fluid at rest with a free surface at a stated pressure. Every view reads the same density, the same surface pressure and the same reference kind, so the pressure field, the path, the plate loading and the buoyancy are all parts of one scene rather than four separate problems.
Model scope
- · The fluid is static, uniform and incompressible; nothing here is moving.
- · Depth h is positive downward from the free surface; elevation z is positive upward. They are never mixed.
- · Every pressure is labelled gauge or absolute. No atmospheric pressure is ever added behind the scenes.
- · The submerged surface is plane and fully submerged in one fluid. Curved surfaces and partly submerged gates are outside this scene.
- · The buoyancy comparison gives the net vertical force only. Floating stability, trim and the metacentre are not modelled.