Bernoulli Pressure Drop
Compute the dynamic pressure difference Δp (Bernoulli) from density ρ and the velocity change.
Inputs
Formula
Δp = ½·ρ·(v2²−v1²)
Faster flow lowers pressure; basis of venturi/nozzle.
Fundamentals
Compute the dynamic pressure difference Δp (Bernoulli) from density ρ and the velocity change.
This tool computes Bernoulli Pressure Drop from the formula: Δp = ½·ρ·(v2²−v1²)
History
Fluid mechanics and heat transfer were established in the 18th–19th centuries with steam engines and thermodynamics.
Engineering applications
Used for piping, heat-exchange and hydraulic system estimates.
Glossary
| Density ρ | Input parameter |
| Upstream v1 | Input parameter |
| Downstream v2 | Input parameter |
| Pressure diff Δp | Output result |
How to use
- Fill in Density ρ, Upstream v1, Downstream v2 in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Pressure diff Δp in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：Δp = ½·ρ·(v2²−v1²)
输入变量：
- Density ρ
rho— kg/m³ - Upstream v1
v1— m/s - Downstream v2
v2— m/s
输出结果：
- Pressure diff Δp
dp— Pa
假设/适用：Flow formulas assume steady, incompressible, continuous flow; correct for compressible/high-speed.
Worked Example
根据公式 Δp = ½·ρ·(v2²−v1²)，取 Density ρ = 1,000 kg/m³；Upstream v1 = 1 m/s；Downstream v2 = 3 m/s。
代入计算得：Pressure diff Δp = 4,000 Pa。
Key Points
- Flow formulas assume steady, incompressible, continuous flow; correct for compressible/high-speed.
- Reynolds Re sets laminar/turbulent; friction f depends on regime & roughness.
- Energy eqn includes elevation, pressure and velocity heads; keep units as length.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Density ρ (kg/m³) | rho | kg/m³ | 1000 |
| Upstream v1 (m/s) | v1 | m/s | 1 |
| Downstream v2 (m/s) | v2 | m/s | 3 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Pressure diff Δp | dp | Pa |
Applications
- Pipe flow rate and pressure drop
- Hydraulic cylinder force/speed design
- Flow-meter selection and calibration
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: Δp = ½·ρ·(v2²−v1²)
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Pipe flow rate and pressure drop