🌊 Surge Tank & Surge Analysis Calculator
Simulate water level oscillations after sudden load rejection using RK4 integration. Evaluate Thoma stability and oscillation period.
🏗️ Surge Tank Schematic
📝 Configuration
Key Equations:
dz/dt = (At/As)Vt
dVt/dt = (g/L)(−z − fLV|V|/(2gD))
Thoma: Acrit = fLV₀²/(2gH₀)
Period: T = 2π√(LAs/(gAt))
dz/dt = (At/As)Vt
dVt/dt = (g/L)(−z − fLV|V|/(2gD))
Thoma: Acrit = fLV₀²/(2gH₀)
Period: T = 2π√(LAs/(gAt))
📊 Results
Configure inputs and click Simulate to view results.
📘 Methodology
Model
The coupled ODEs for surge tank level and tunnel velocity are integrated using 4th-order Runge-Kutta. Friction damping causes the oscillation amplitude to decay over time.
Thoma Criterion
If the tank cross-sectional area is less than the Thoma critical area, oscillations grow instead of decaying — indicating an unstable design.
Assumptions
- Rigid water column (no elastic effects).
- Sudden full load rejection.
- Simple cylindrical surge tank.
- No throttling or orifice at tank base.