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# Dynamic pressure

Dynamic pressure (sometimes called velocity pressure) is the increase in a moving fluid's pressure over its static value due to motion. 

## Aerodynamics

Aerodynamics, from Greek ἀήρ aer (air) + δυναμική (dynamics), is the study of the motion of air, particularly its interaction with a solid object, such as an airplane wing.

## Bernoulli's principle

In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

## Closed system

A closed system is a physical system that does not allow certain types of transfers (such as transfer of mass and energy transfer) in or out of the system.

## Conservation of energy

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant, it is said to be ''conserved'' over time.

## Density

The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.

## Dimensional analysis

In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities (such as length, mass, time, and electric charge) and units of measure (such as miles vs. kilometers, or pounds vs. kilograms) and tracking these dimensions as calculations or comparisons are performed.

## Drag coefficient

In fluid dynamics, the drag coefficient (commonly denoted as: \scriptstyle C_\mathrm d\,, \scriptstyle C_\mathrm x\, or \scriptstyle C_\mathrm w\) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water.

## First law of thermodynamics

The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems.

## Flow velocity

In continuum mechanics the macroscopic velocity, also flow velocity in fluid dynamics or drift velocity in electromagnetism, is a vector field used to mathematically describe the motion of a continuum.

## Fluid dynamics

In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids - liquids and gases.

## Gas constant

The gas constant is also known as the molar, universal, or ideal gas constant, denoted by the symbol or and is equivalent to the Boltzmann constant, but expressed in units of energy per temperature increment per mole, i.e. the pressure-volume product, rather than energy per temperature increment per particle.

## Heat capacity ratio

In thermal physics and thermodynamics, the heat capacity ratio or adiabatic index or ratio of specific heats or Poisson constant, is the ratio of the heat capacity at constant pressure to heat capacity at constant volume.

Hydraulic head or piezometric head is a specific measurement of liquid pressure above a geodetic datum.

## Ideal gas

An ideal gas is a theoretical gas composed of many randomly moving point particles whose only interactions are perfectly elastic collisions.

## Ideal gas law

The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas.

## Impact pressure

In compressible fluid dynamics, impact pressure (dynamic pressure) is the difference between total pressure (also known as pitot pressure or stagnation pressure) and static pressure.

## Incompressible flow

In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric flow) refers to a flow in which the material density is constant within a fluid parcel—an infinitesimal volume that moves with the flow velocity.

## International System of Units

The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.

## Kelvin

The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.

## Kinetic energy

In physics, the kinetic energy of an object is the energy that it possesses due to its motion.

## Laurence Joseph Clancy

Laurence Joseph Clancy (15 March 1929 to 16 October 2014) was an Education Officer in aerodynamics at Royal Air Force College Cranwell whose textbook became standard.

## Lift coefficient

The lift coefficient (CL, CN or Cz) is a dimensionless coefficient that relates the lift generated by a lifting body to the fluid density around the body, the fluid velocity and an associated reference area.

## Mach number

In fluid dynamics, the Mach number (M or Ma) is a dimensionless quantity representing the ratio of flow velocity past a boundary to the local speed of sound.

## Max Q

In aerospace engineering, the maximum dynamic pressure, often referred to as maximum Q or max Q, is the point at which aerodynamic stress on a vehicle in atmospheric flight is maximized.

## Pascal (unit)

The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength.

## Pitching moment

In aerodynamics, the pitching moment on an airfoil is the moment (or torque) produced by the aerodynamic force on the airfoil if that aerodynamic force is considered to be applied, not at the center of pressure, but at the aerodynamic center of the airfoil.

## Pressure

Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.

In fluid mechanics, pressure head is the internal energy of a fluid due to the pressure exerted on its container.

## Pressure measurement

Pressure measurement is the analysis of an applied force by a fluid (liquid or gas) on a surface.

## Properties of water

Water is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. It is also the third most abundant molecule in the universe. Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows it to separate ions in salts and strongly bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar mass, and a high heat capacity. Water is amphoteric, meaning that it is both an acid and a base—it produces + and - ions by self-ionization.

## Speed of sound

The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium.

## Stagnation pressure

In fluid dynamics, stagnation pressure (or pitot pressure) is the static pressure at a stagnation point in a fluid flow.

## Standard gravity

The standard acceleration due to gravity (or standard acceleration of free fall), sometimes abbreviated as standard gravity, usually denoted by or, is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth.

## Static pressure

In fluid mechanics the term static pressure has several uses.

## Stress (mechanics)

In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material.

## Thermodynamic temperature

Thermodynamic temperature is the absolute measure of temperature and is one of the principal parameters of thermodynamics.