🌀 Taylor-Couette Flow Stability & Vortex Cells

Compute Taylor number (Ta), critical onset speed (N1c), toroidal Taylor vortex pair wavelength (λ ≈ 2d), and viscous rotor torque in concentric rotating cylinders.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated
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📅 Mise en service Jun 2026
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🌀 Concentric Rotating Cylinders & Toroidal Taylor Vortex Cells

Real-time visual simulation of centrifugal instability vortex pairs forming between inner rotor & outer stator

📝 Configuration & Presets

🧪 Water Rheometer (150 RPM) 🛢️ Oil Journal Bearing 🧫 Vortex Bioreactor ⚡ Rotating Electrode (RCE)
📐 Cylinder Dimensions & Rotation
💧 Fluid Physical Properties
Water: 1.0 cSt, Light Oil: 10–32 cSt
Taylor-Couette Stability Formulations:
• Taylor Number: Ta = [ 2 Ω₁² R₁ d³ ] / [ ν² (1 + η) ]
• Critical Stability: Tac ≈ 1708 / (1 − 0.652 d/R₁)
• Critical Speed: N1,c = (60/2π) · √[ Tac ν² (1+η) / (2 R₁ d³) ]
• Vortex Pair Wavelength: λ ≈ 2 d [mm]

📊 Hydrodynamic Stability Results

📊 Output Summary
💾 Fortran Source

Taylor Number (Ta)
Ta = 31,595 (Ta / Tac = 17.90)
Regime: 〰️ Modulated Wavy Vortex
N1,c = 709.2 RPM
Critical Onset Speed (N1,c) 709.2 RPM Operating: 3000.0 RPM
Toroidal Vortex Wavelength (λ) 4.0 mm 20.0 vortex pairs
Viscous Rotor Torque 0.2446 N·m Power: 76.85 W
Annular Gap Ratio (η = R₁/R₂) 0.952 Gap d = 2.0 mm

📈 Taylor Number (Ta) vs Rotor Speed (RPM)

📉 Viscous Torque (N·m) vs Kinematic Viscosity (cSt)

=================================================================
 THERMOFLUIDCALC — TAYLOR-COUETTE HYDRODYNAMIC REPORT
=================================================================
Case Title                 : High-Speed Lubrication Journal Bearing Sleeve
Cylinder Radii (R1 x R2)   : 40.00 mm x 42.00 mm (Gap d = 2.00 mm, eta = 0.952)
Cylinder Height (H)        : 80.0 mm
Inner Rotor Speed (N1)     : 3000.0 RPM
Fluid Kinematic Viscosity  : 32.00 cSt (Density = 870.0 kg/m3)
-----------------------------------------------------------------
TAYLOR NUMBER (Ta)         : 31,594.8
Critical Taylor (Ta_c)     : 1,765.6
CRITICAL ONSET SPEED (N1c) : 709.18 RPM
Hydrodynamic Regime        : 〰️ Modulated Wavy Vortex
Taylor Vortex Wavelength   : 4.00 mm (20.0 cell pairs)
Viscous Torque & Power     : 0.24462 N.m / 76.848 Watts
=================================================================

📘 Calculation Methodology & Taylor Stability Standards

Centrifugal Instability Mechanism

When the inner cylinder rotates faster than the outer wall, centrifugal forces destabilize the fluid element, giving birth to toroidal Taylor vortices when $Ta > Ta_c \approx 1708$:

Ta = [ 2 Ω₁² R₁ d³ ] / [ ν² (1 + η) ]

Toroidal Vortex Cells Structure

Each pair of toroidal vortex cells occupies an axial wavelength $\lambda \approx 2d$, rotating in alternating counter-clockwise and clockwise directions.

Key Engineering Assumptions

  • Isothermal Newtonian fluid with constant kinematic viscosity.
  • Narrow to medium annular gap ($0.5 \le \eta \le 0.98$).
  • Negligible end-wall Ekman layer perturbations.