Bernoulli Dynamic Pressure Drop & Venturi Calculator
Along a horizontal streamline of inviscid incompressible flow, Bernoulli's principle states that accelerating a fluid from velocity v₁ to throat velocity v₂ produces a static pressure drop ΔP = 0.5 × ρ × (v₂² - v₁²).
Pressure differential P₁ - P₂ in Pascals
Fluid mass density in kg/m³ (Water = 1000, Air = 1.225)
Constricted high-speed flow velocity in m/s
Inlet approach velocity in m/s
Step-by-Step Calculation
Along a horizontal streamline of inviscid incompressible flow, Bernoulli's principle states that accelerating a fluid from velocity v₁ to throat velocity v₂ produces a static pressure drop ΔP = 0.5 × ρ × (v₂² - v₁²).
Real-World Reference Values
Aircraft airspeed indicator fundamental equation
Low permanent head loss vs orifice plates (C_d ≈ 0.61)
Excessive throat velocity flashes liquid into vapor bubbles
20-Row Comparison Table
Static Pressure Drop (ΔP) · Fluid Density (ρ (kg/m³))
| # | Fluid Density (ρ (kg/m³)) | Static Pressure Drop (Pa) | Δ % |
|---|---|---|---|
| 01 | 0.1 | 1.8 Pa | -99.99% |
| 02 | 161.2782 | 2,903.01 Pa | -83.87% |
| 03 | 322.4564 | 5,804.22 Pa | -67.75% |
| 04 | 483.6347 | 8,705.42 Pa | -51.64% |
| 05 | 644.8129 | 11,606.63 Pa | -35.52% |
| 06 | 805.9911 | 14,507.84 Pa | -19.40% |
| 07 | 1,000.00 Current | 18,000.00 Pa | 0.00% |
| 08 | 1,128.35 | 20,310.25 Pa | +12.83% |
| 09 | 1,289.53 | 23,211.46 Pa | +28.95% |
| 10 | 1,450.70 | 26,112.67 Pa | +45.07% |
| 11 | 1,611.88 | 29,013.88 Pa | +61.19% |
| 12 | 1,773.06 | 31,915.08 Pa | +77.31% |
| 13 | 1,934.24 | 34,816.29 Pa | +93.42% |
| 14 | 2,095.42 | 37,717.50 Pa | +109.54% |
| 15 | 2,256.60 | 40,618.71 Pa | +125.66% |
| 16 | 2,417.77 | 43,519.92 Pa | +141.78% |
| 17 | 2,578.95 | 46,421.12 Pa | +157.90% |
| 18 | 2,740.13 | 49,322.33 Pa | +174.01% |
| 19 | 2,901.31 | 52,223.54 Pa | +190.13% |
| 20 | 3,062.49 | 55,124.75 Pa | +206.25% |
Frequently Asked Questions
How do I use this calculator as a Pitot tube airspeed solver?+
Set Upstream Velocity v₁ = 0, enter air density ρ = 1.225 kg/m³, and click SOLVE FOR on v₂ to compute airspeed from Pitot dynamic pressure ΔP.
Why does pressure drop when a pipe narrows?+
By conservation of energy along a streamline, an increase in kinetic energy per unit volume (½ρv²) requires an equal decrease in static pressure P.
What if there is also an elevation change Δz?+
Add hydrostatic head ρ × g × (z₂ - z₁) to the dynamic pressure drop for inclined pipes.