Fluid Dynamics (Bernoulli, Continuity, Flow Rate) — A/L Physics

What must I remember about Fluid Dynamics (Bernoulli, Continuity, Flow Rate)?

• Streamline and Turbulent Flow: Streamline (laminar) flow occurs when every passing fluid particle follows identical smooth trajectories without crossing; Turbulent flow occurs when velocity exceeds critical speed, forming chaotic mixing vortices and eddies.
• Equation of Continuity: Mass conservation in steady incompressible flow: A1 * v1 = A2 * v2 = Volume flow rate Q (m³/s); fluid velocity is inversely proportional to pipe cross-sectional area.
• Bernoulli's Equation: Energy conservation per unit volume along a streamline for steady, incompressible, non-viscous fluid flow: P + (1/2) ρ v² + ρ g h = Constant.
• Physical Interpretations of Bernoulli Terms: Static Pressure P (potential energy due to pressure forces); Dynamic Pressure (1/2) ρ v² (kinetic energy per unit volume); Hydrostatic Pressure ρ g h (gravitational potential energy per unit volume).

Test yourself (1 minute)

1. Venturi Effect

   When fluid flows into a constricted throat (smaller A), velocity increases (v2 > v1) and static pressure drops (P2 < P1); Pressure differential ΔP = P1 - P2 = (1/2) ρ (v2² - v1²); utilized in carburetors, aspirators, and flow meters.

2. Pitot-Static Tube

   Measures flow airspeed by comparing Stagnation Pressure P_stag = P_static + (1/2) ρ v² at forward-facing tube tip (where fluid is brought to rest v = 0) with Static Pressure P_static from side flush holes: Airspeed v = √[ (2 (P_stag - P_static)) / ρ ].

3. Magnus Effect (Spinning Ball)

   A spinning cylinder or ball drags boundary air layer around it, creating higher velocity and lower pressure on one side, resulting in sideways aerodynamic deflection force (curveballs in cricket and football).

Practise Fluid Dynamics (Bernoulli, Continuity, Flow Rate) questions today

Source: NIE G.C.E. (A/L) Physics Resource Book - Unit 10: Fluid Dynamics

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Where does Fluid Dynamics (Bernoulli, Continuity, Flow Rate) fit in the syllabus?

Unit 10.6 · Year 2 · Term 3