🌀 Flow Around Cylinders Calculator
Compute vortex shedding frequency, Strouhal number, drag/lift coefficients, and lock-in velocity range for circular cylinders in cross-flow. Classifies Reynolds regime.
🌬️ Vortex Shedding Schematic
📝 Configuration
Key Equations:
St = fD/V∞ (Strouhal number)
St ≈ 0.198(1−19.7/Re) subcritical
Lock-in: 0.8fn < fshed < 1.2fn
FD/L = ½ρV²DCD
St = fD/V∞ (Strouhal number)
St ≈ 0.198(1−19.7/Re) subcritical
Lock-in: 0.8fn < fshed < 1.2fn
FD/L = ½ρV²DCD
📊 Results
Configure inputs and click Analyze to view results.
📘 Methodology
Vortex Shedding
Periodic vortex shedding from a cylinder creates alternating lift forces. The Strouhal number St ≈ 0.20 in the subcritical range (300 < Re < 3×10⁵) and increases during the drag crisis.
Lock-in / VIV
When shedding frequency approaches the structure's natural frequency (0.8fn to 1.2fn), vortex-induced vibration can cause resonance and fatigue failure.
Regime Classification
- Re < 5: creeping flow
- 5–40: steady twin vortices
- 40–200: laminar vortex street
- 200–3×10⁵: subcritical
- 3×10⁵–3.5×10⁶: critical/supercritical
- >3.5×10⁶: transcritical