Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

# Technical Terms in Fluid Mechanics

## Some of the most commonly used technical terms 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.

### 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.

### 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.

### 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 measurement

• Fluid Flow-meters - 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

### 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.

### 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.

### 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.

### 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.

### 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.

## Related Topics

• Hydraulics and Pneumatics - Hydraulic and pneumatic systems - fluids, forces, pumps and pistons
• Fluid Mechanics - The study of fluids - liquids and gases. Involves velocity, pressure, density and temperature as functions of space and time

## Engineering ToolBox - SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

Translate

## Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

## Citation

• Engineering ToolBox, (2003). Technical Terms in Fluid Mechanics. [online] Available at: https://www.engineeringtoolbox.com/technical-terms-fluid-mechanics-d_181.html [Accessed Day Mo. Year].

Modify access date.

. .

#### Scientific Online Calculator 10 15