Resumo de Mecânica dos Fluidos

Cartões · 52

Bernoulli's Principle

An airplane wing generates aerodynamic lift because air travels faster over the curved top surface, reducing pressure relative to the bottom.

Venturi Effect

A traditional automotive carburetor draws liquid gasoline into a narrow throat where passing airflow accelerates and drops in pressure.

Pascal's Law

Hydraulic car jacks multiply input force by transmitting external fluid pressure undiminished across a larger output piston.

Archimedes' Principle

A massive steel cargo ship floats because its hollow hull displaces a volume of seawater whose total weight equals the ship's weight.

Laminar Flow

Syrup pouring slowly from a bottle forms a smooth, glassy, and unmixed stream with parallel fluid layers sliding past each other.

Turbulent Flow

White-water rapids exhibit chaotic swirling eddies, rapid mixing, and pressure fluctuations as water rushes past jagged boulders.

Reynolds Number

Wind tunnel engineers scale scale-model aircraft tests to match the ratio of inertial to viscous forces experienced by full-sized planes.

Viscosity

Motor oil is formulated with high viscosity to maintain a lubricating barrier film between sliding engine parts under high heat.

Non-Newtonian Fluid (Shear-Thickening)

Oobleck (cornstarch and water) hardens instantaneously into a near-solid state when struck with a hammer due to rapid stress increase.

Non-Newtonian Fluid (Shear-Thinning)

House paint spreads easily under a moving brush due to reduced viscosity under shear, but does not drip once applied to the wall.

Surface Tension

Water strider insects walk on pond surfaces without sinking because cohesive water molecule forces create an elastic-like membrane.

Capillary Action

A paper towel rapidly absorbs spilled coffee upward against gravity through microscopic porous cellulose fibers.

Cavitation

Ship propellers spinning at high speeds form low-pressure vapor bubbles that violently collapse, eroding and pitting the metal blades.

Water Hammer

Rapidly shutting off a high-pressure home sink faucet causes a loud banging sound due to a sudden acoustic pressure shockwave in the pipe.

Boundary Layer

Dust clings to high-speed automotive fan blades because fluid velocity drops to zero right at the blade surface due to the no-slip condition.

No-Slip Condition

Oil adhering directly to the stationary inner wall of an industrial pipeline remains completely motionless despite fast core flow.

Magnus Effect

A soccer player's curved free kick bends laterally mid-air because ball spin creates asymmetric airflow velocity and pressure.

Coanda Effect

Water running from a kitchen faucet clings to and curves around the back of a spoon brought close to the stream.

Torricelli's Law

Water draining from an opening at the bottom of an elevated municipal storage tank flows out faster when the tank is completely full.

Poiseuille Flow

Arteries partially narrowed by plaque require the heart to exert drastically higher pumping pressure to sustain normal blood volume flow.

Couette Flow

Lubricating fluid shearing between a rotating inner axle shaft and a stationary outer journal bearing creates a steady velocity gradient.

Vortex Shedding

The collapse of the original Tacoma Narrows Bridge was triggered by alternating vortices peeling off the structure in steady winds.

Kármán Vortex Street

Clouds drifting past isolated volcanic ocean islands form alternating swirling spiral wake patterns visible from weather satellites.

Stoke's Law

Tiny fine silt particles settle extremely slowly to the bottom of a quiet lake due to high viscous drag relative to their weight.

Mach Cone / Sonic Boom

A supersonic fighter jet outruns its own pressure waves, creating a sharp conical shock front that sounds like an explosion on the ground.

Hydraulic Jump

The abrupt transition from a thin, fast-moving water sheet to a deeper, turbulent frothy pool directly beneath a kitchen sink tap.

Siphon Effect

Emptying a home fish tank using a submerged hose running down to a lower bucket relies on hydrostatic head and continuous liquid cohesion.

Darcy-Weisbach Friction Loss

Designing long-distance municipal water supply lines requires choosing pipe diameter and material to overcome pressure drop from wall roughness.

Compressible Flow

Gases exiting a rocket nozzle change dramatically in density and temperature as they accelerate from subsonic to supersonic speeds.

Incompressible Flow Assumption

Water flowing through a residential plumbing network is treated as having constant density regardless of local velocity or pressure.

Pitot Tube

Commercial aircraft measure flight airspeed by converting dynamic fluid motion into stagnation pressure measured inside a forward probe.

Buoyancy (Thermal Plume)

Hot air balloons rise through the cooler morning atmosphere because the less dense trapped warm air generates net upward lift.

Rayleigh-Taylor Instability

Pouring heavy cold cream into warm black coffee causes intricate finger-like descending plumes as the denser fluid sinks through the lighter one.

Kelvin-Helmholtz Instability

Strong ocean winds blowing over water produce curling wave crests resembling breaking billow clouds seen across distinct atmospheric layers.

Skin Friction Drag

Competitive Olympic swimmers wear ultra-smooth, tight bodysuits to minimize shearing resistance against skin-adjacent water layers.

Form (Pressure) Drag

Semi-trailer trucks attach blunt cab air fairings to eliminate wide wake separation zones behind the cab, saving diesel fuel.

Wave Drag

Supersonic aircraft feature needle-thin noses and swept wings to minimize shockwave formation resistance when breaching Mach 1.

Induced Drag

Modern commercial airliners install vertical winglets at wingtips to weaken vortices spun off by high-pressure air curling over the top.

Flow Separation

An airplane wing tilting up at too high an angle of attack suffers airflow detachment, leading to an immediate aerodynamic stall.

Choked Flow

A ruptured industrial gas cylinder cannot vent its contents any faster once gas exit velocity reaches Mach 1 at the valve throat.

Prandtl-Meyer Expansion Fan

Supersonic gas jets expanding out into vacuum past the edge of a rocket engine nozzle bell turn outward while accelerating and cooling.

Normal Shock Wave

Air passing abruptly into a ramjet engine intake drops from supersonic to subsonic speed across a paper-thin, high-entropy discontinuity.

Manometer Hydrostatics

A transparent U-shaped glass tube filled with colored liquid measures HVAC duct pressure differences by balancing liquid column heights.

Centrifugal Pumping

A household sump pump uses a spinning impeller to accelerate water radially outward, converting kinetic energy into discharge pressure.

Slug Flow

Offshore petroleum pipelines experience dangerous vibrations when alternating large pockets of natural gas and liquid oil surge through.

Meneghini / Marangoni Effect

Wine tears forming inside a glass occur because alcohol evaporates faster near the rim, driving liquid upward along surface tension gradients.

Hydrodynamic Lubrication

Automobile tires hydroplane over flooded roads when a wedge of standing water builds enough upward fluid pressure to lift rubber off asphalt.

Thixotropy

Drilling mud stays thick and gel-like to suspend rock cuttings when stationary, but thins into an easily pumped liquid when rotated.

Taylor-Couette Flow

Fluid trapped between two independently spinning concentric cylinders organizes into distinct stacked toroidal vortex rings at critical speeds.

Secondary Flow in Bends

Meandering natural rivers scour sand from outer bends and deposit gravel on inside banks due to helical, spiral water circulation.

Acoustic Levitation

Intense standing sound waves in laboratory chambers suspend tiny liquid droplets mid-air at pressure nodes against gravity.

Eulerian vs. Lagrangian Description

Oceanographers measure ocean currents using fixed seafloor flow sensors (Eulerian) versus drifting GPS buoys tracked over time (Lagrangian).