Technical Terms in Fluid Mechanics

Some of the most common used technical terms used in fluid mechanics

Acoustic theory

• Relating to mathematical description of sound waves.
• Acoustical Engineering - Explains to architects and engineers the basic science of acoustics. Introduction to sound, decibel and propagation of sound. Calculate decibels, reduce noise in HVAC systems, sound levels ..

Aerodynamics

• Aerodynamics is the study of the flow of gases.
• The Ideal Gas Law - For a perfect or ideal gas the change in density is directly related to the change in temperature and pressure as expressed in the Ideal Gas Law.

Aeronautics

• Aeronautics is the mathematics and mechanics of flying objects, in particular airplanes.

Bernoulli's equation

• The Bernoulli's Equation describes the behavior of moving fluids along a streamline.

Boundary layer

• The boundary layer is the layer of fluid in the immediate vicinity of a bounding surface.
• Dynamic, Absolute and Kinematic Viscosity - An introduction to dynamic, absolute and kinematic viscosity and how to convert between CentiStokes (cSt), CentiPoises (cP), Saybolt Universal Seconds (SSU) and degree Engler.

Cavitations

• Cavitation and NPSH - An introduction to cavitation and Net Positive Suction Head, NPSH.
• Cavitation in Control Valves - Control valves and cavitation, application ratio and multi stage control valves.

Compressible flow

• In a compressible flow the compressibility of the fluid must be taken into account.
• The Ideal Gas Law - For a perfect or ideal gas the change in density is directly related to the change in temperature and pressure as expressed in the Ideal Gas Law.
• Properties of Gas Mixtures - Special care must be taken for gas mixtures when using the ideal gas law, calculating the mass, the individual gas constant or the density.
• The Individual and Universal Gas Constant - The Individual and Universal Gas Constant is common in fluid mechanics and thermodynamics.
  

Coanda effect

• The Coanda Effect is the tendency of a stream of fluid to stay attached to a convex surface, rather than follow a straight line in its original direction.

Conservation laws

• The conservation laws states that particular measurable properties of an isolated physical system does not change as the system evolves.
• conservation of energy (including mass)
• Fluid Mechanics and Conservation of Mass - The law of conservation of mass states that mass can neither be created or destroyed.

Darcy-Weisbach Equation

• Pressure Loss and Head Loss due to Friction in Ducts and Tubes - Major loss - head loss or pressure loss - due to friction in pipes and ducts.

Density

• Density, Specific Weight and Specific Gravity - An introduction and definition of density, specific weight and specific gravity. Formulas with examples.

Euler equations

• In fluid dynamics, the Euler equations govern the motion of a compressible, inviscid fluid. They correspond to the Navier-Stokes equations with zero viscosity, although they are usually written in the form shown here because this emphasizes the fact that they directly represent conservation of mass, momentum, and energy.

Euler Number

• The Euler Number - An introduction to and a definition of the Euler Number.

Flow Coefficient - C_v - K_v

• Flow Coefficient Cv and Flow Factor Kv - The difference between the flow coefficient Cv and Kv.

Flow measurement

• Fluid Flowmeters - Tools and information regarding fluid flowmeters.
• Fluid Flow Measurement - An introduction to different types of fluid flowmeters - Orifices, Venturies, Nozzles, Rotameters, Pitot Tubes, Calorimetrics, Turbine, Vortex, Electromagnetic, Doppler, Ultrasonic, Thermal, Coriolis.

Fluids

• The Bernoulli Equation - A statement of the conservation of energy in a form useful for solving problems involving fluids. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point.
• Equations in Fluid Mechanics - Continuity, Euler, Bernoulli, Dynamic and Total Pressure
• Laminar, Transitional or Turbulent Flow? - It is important to know if the fluid flow is laminar, transitional or turbulent when calculating heat transfer or pressure and head loss.

Froude number

• The Froude Number - An introduction to and a definition of the Froude Number.

Gas

• The Ideal Gas Law - For a perfect or ideal gas the change in density is directly related to the change in temperature and pressure as expressed in the Ideal Gas Law.
• Properties of Gas Mixtures - Special care must be taken for gas mixtures when using the ideal gas law, calculating the mass, the individual gas constant or the density.
• The Individual and Universal Gas Constant - The Individual and Universal Gas Constant is common in fluid mechanics and thermodynamics.

Hydraulics

• Hydraulics is a branch of science and engineering concerned with the use of liquids to perform mechanical tasks.

Hydrodynamics

• Hydrodynamics is the fluid dynamics applied to liquids, such as water, alcohol, and oil.

Ideal Gas

• The Ideal Gas Law - For a perfect or ideal gas the change in density is directly related to the change in temperature and pressure as expressed in the Ideal Gas Law.
• Properties of Gas Mixtures - Special care must be taken for gas mixtures when using the ideal gas law, calculating the mass, the individual gas constant or the density.
• The Individual and Universal Gas Constant - The Individual and Universal Gas Constant is common in fluid mechanics and thermodynamics.

Knudsen number

• Used by modelers who wish to non dimensionless speed

Laminar Flow

• Laminar, Transitional or Turbulent Flow? - It is important to know if the fluid flow is laminar, transitional or turbulent when calculating heat transfer or pressure and head loss.

Laplace's equation

• Describes the behavior of gravitational, electric, and fluid potentials.

Lift (force)

• Lift consists of the sum of all the aerodynamic forces normal to the direction of the external airflow.

Liquids

• Equations in Fluid Mechanics - Continuity, Euler, Bernoulli, Dynamic and Total Pressure

Mach number

• When an object travels through a medium, then its Mach number is the ratio of the object's speed to the speed of sound in that medium.
• The Mach Number - An introduction to and a definition of the Mach Number.

Navier-Stokes Equations

• The motion of a non-turbulent, Newtonian fluid is governed by the Navier-Stokes equation. The equation can be used to model turbulent flow, where the fluid parameters are interpreted as time-averaged values.

Newtonian Fluid

• A fluid is Newtonian if viscosity is constant applied to shear force.
• Dynamic, Absolute and Kinematic Viscosity - An introduction to dynamic, absolute and kinematic viscosity and how to convert between CentiStokes (cSt), CentiPoises (cP), Saybolt Universal Seconds (SSU) and degree Engler.

Non-Newtonian fluid

• Non-Newtonian fluid viscosity changes with the applied shear force.

Prandtl number

• Prandtl Number is a Dimensionless number approximating the ratio of momentum diffusivity and thermal diffusivity.

Pressure

• What is Pressure? - An introduction to pressure, a definition and a presentation of common units as psi and Pa, and the relationship between them.

Reynolds Number

• The Reynolds Number - An introduction to and a definition of the dimensionless Reynold's Number.
• An Online Reynolds Number Calculator - Calculate laminar or turbulent flow with the Reynolds number online calculator.
• Reynold's Number in Water Tubes - Reynolds Number in tubes at different dimensions transporting clean cold water.

Richardson number

• A dimensionless number that expresses the ratio of potential to kinetic energy.

Reynolds number

• The Reynolds number is used for determine whether a flow is laminar or turbulent.
• The Reynolds Number - An introduction to and a definition of the dimensionless Reynold's Number.
• Reynold's Number in Water Tubes - Reynolds Number in tubes at different dimensions transporting clean cold water.

Shock wave

• A shock wave is a strong pressure wave produced by explosions or other phenomena that create violent changes in pressure.

Sound barrier

• The sound barrier is the apparent physical boundary stopping large objects from becoming supersonic.
• The Mach Number - An introduction to and a definition of the Mach Number.
• Speed of Sound - Speed of sound in air, fluids and solids. Formulas and values for different materials.

Streamline - Stream function

• a streamline is the path that an imaginary particle would follow if it was embedded in the flow.

Strouhal number

• The Strouhal number is a quantity describing oscillating flow mechanisms.
• The Strouhal Number - An introduction to and a definition of the Strouhal Number.

Supersonic Flow

• Flow with speed above the speed of sound, 1,225 km/h at sea level, is said to be supersonic.
• The Mach Number - An introduction to and a definition of the Mach Number.
• Speed of Sound - Speed of sound in air, fluids and solids. Formulas and values for different materials.

Surface tension

• Surface tension is a force within the surface layer of a liquid that causes the layer to behave as an elastic sheet.

Transonic

• Flow with speed at velocities just below and above the speed of sound is said to be transonic.
• The Mach Number - An introduction to and a definition of the Mach Number.

Turbulent Flow - Turbulence

• Laminar, Transitional or Turbulent Flow? - It is important to know if the fluid flow is laminar, transitional or turbulent when calculating heat transfer or pressure and head loss.

Vapor pressure

• For a particular substance at any given temperature there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms.

Velocity

• The Bernoulli Equation - A statement of the conservation of energy in a form useful for solving problems involving fluids. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point.

Venturi

• A Venturi is a system for speeding the flow of the fluid, by constricting it in a cone-shaped tube.

Viscosity

• Dynamic, Absolute and Kinematic Viscosity - An introduction to dynamic, absolute and kinematic viscosity and how to convert between CentiStokes (cSt), CentiPoises (cP), Saybolt Universal Seconds (SSU) and degree Engler.
• Kinematic Viscosity of Common Fluids - Kinematic viscosity of fluids as motor oil, diesel fuel, peanut oil and many more.
• Online Absolute or Dynamic Viscosity Calculator - Calculate absolute or dynamic viscosity between centipoise, reyn and more.
• Online Kinematic Viscosity Calculator - Calculate dynamic viscosity between centistokes, poise, lentor and more.
• Online Dynamic Viscosity Converter for Oil and Water - Convert between dynamic viscosity units for oil and water.
• A Viscosity Converting Chart - A table converting between Centiposes, milliPascal, CentiStokes and SSU.
• Absolute or Dynamic Viscosity of Water - Absolute or dynamic viscosity of water depends on the temperature.

Vorticity

• Vorticity is defined as the circulation per unit area at a point in the flow field.
• The Vortex Flow meter Principle - An introduction to the vortex flowmeter principle.

Wave drag

• Wave drag refer to a sudden and very powerful drag that appears on aircrafts flying at high-subsonic speeds.

Weber Number

• The Weber Number - An introduction to and a definition of the Weber Number.

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