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Lesson 13 'තරල යන්ත්‍ර' (Fluid Mechanics) හි ප්‍රධාන මාතෘකා:

• 💧 Fluid Properties — Density (ρ), Specific gravity, Viscosity (μ), Surface tension
• 📊 Fluid Pressure — Gauge, Absolute, Atmospheric; P = ρgh
• ⚖️ Pascal's Law — Pressure transmitted equally in all directions
• 🌊 Hydrostatic Forces on submerged surfaces; buoyancy (Archimedes' principle)
• 🔄 Continuity Equation: A₁V₁ = A₂V₂ (mass conservation)
• 📐 Bernoulli's Equation: P/ρg + V²/2g + z = constant (energy conservation)
• 📏 Flow Measurement — Venturimeter, Orifice meter, Pitot tube
• 🔬 Reynolds Number (Re) — Laminar (<2000) vs Turbulent (>4000) flow
• 🌀 Centrifugal Pumps & Hydraulic Turbines (Pelton, Francis, Kaplan)

Bernoulli's Equation — Energy conservation along a streamline:

P/ρg + V²/2g + z = constant  |  (Pressure + Velocity + Elevation head)

Continuity Equation:

A₁V₁ = A₂V₂  — as area ↓, velocity ↑, pressure ↓

Reynolds Number:

Re = ρVD/μ  |  <2000 Laminar  |  >4000 Turbulent

AL Tech Hub (altechhub.lk) හි Lesson 13 Downloads කොටසෙන් නොමිලේ ලබාගත හැකිය:

• 📄 Full Notes PDF — 7.2 MB, 96 pages
• 📄 Fluid Properties & Pressure Guide — 2.5 MB, 24 pages
• 📄 Bernoulli & Flow Equations — 2.8 MB, 28 pages
• 📄 Flow Measurement Devices — 2.2 MB, 22 pages
• 📄 Pumps & Turbines Guide — 3.0 MB, 30 pages
• 📊 Slide Deck (PPTX) — 9.8 MB, 62 slides
• 📝 Practice Q&A (DOCX), Past Papers, 🗜️ Complete Bundle (ZIP 32 MB)

Hydraulic Turbines:

• Pelton (Impulse) — High head (>200m), low flow; jet strikes buckets
• Francis (Mixed flow) — Medium head (40–200m); most common
• Kaplan (Axial) — Low head (<40m), high flow; adjustable blades

Centrifugal Pump:

• Impeller rotation → centrifugal force → pressure increase
• Efficiency: η = ρgQH / P_input × 100%
• Cavitation — vapour bubbles form when pressure drops below vapour pressure