## V : Sound and Vibration Terms, Definitions, Units, Measurements ...

*VDV •* Vibration Dose Value

**Vector spaces** are applied throughout mathematics, science and engineering. They are the linear-algebraic notion to deal with systems of linear equations; offer a framework for Fourier expansion or provide an environment that can be used for solution techniques for partial differential equations.

**Velocity of Sound** is usually taken to mean the

speed of sound.

Not be confused with sound particle velocity, which is the velocity of the individual particles of the

medium the sound wave is passing through. To add to the confusion the unit v is often included.

**Vibration** is the movement of particles in an elastic medium about an

equilibrium position. The movement may be periodic such as the motion of a pendulum or random.

Vibration is commonly expressed in terms of
acceleration,
velocity,
displacement and
frequency which are related.

Vibration Acceleration Level

**Vibration at Work Regulations**, came into force in July 2005 to protect workers from risks to their health from vibration, based on

hand arm and

whole body vibration **exposure action and limiting values**.

Vibration Dose Value

Vibration Exposure Action Value
Vibration Exposure Limit Value

Vibration Nomogram for downloading.

**Vibration Parameters**
Acceleration
Velocity
Displacement

Vibration Reference Levels

Vibration Regulations, see Vibration at Work Regulations

**Vibration Velocity** under

velocity

Vibration Weighting Networks

Vibration White Finger

Vibratory Acceleration Level
Vibratory Velocity Level

**Viscous Damping Definition IEC 801-24-22,** damping that occurs when a particle in an

oscillating system is resisted by a force that has a magnitude proportional to the magnitude of the velocity of the particle and direction opposite to the direction of the particle

See also other damping topics.

**Volt (V)**, the derived

SI unit of electric potential; the potential difference between two points on a conductor carrying a current of 1

ampere, when the

power dissipated between these points is 1 watt

**Voltage Level (LV)** is the voltage expressed in

decibels, relative to 1 volt

rms, regardless of impedance.

LV = 20 lg (V/Vo) dBV

The reference voltage : Vo = 1 volt ≡ 0 dB

**Volume (V)**, a

scalar quantity is the amount of space that an object or substance occupies, the SI unit is the metre-cubed (m

^{3}).

**Volumetric Flow Rate (Q)** is the volume of fluid which passes through a given surface per unit time.

*Q = v·A,* where v = velocity, A = area/surface and the SI units are m^{3}/s.

*Volumetric flow rate* is also known as the *volume flow rate*, *rate of fluid flow* and *volume velocity*

**Volumetric Flux (q)** is the volumetric flow rate across a unit area. SI units : m^{3}·s^{-1}·m^{-2}

**Volumetric Power Density**, volume based power density - watt/m^{3}

**Volume Velocity Definition IEC 801-21-31,** integral, over a vibration surface, of the product of the component of

particle velocity normal to the surface and the differential

surface area. Also known as

*sound volume velocity*,

*volumetric flow rate* and

*volume flow rate*
See also • velocity.

*VWF : Vibration White Finger*, see

Hand Arm Vibration

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