Aero formulas: Difference between revisions

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m (fix delta H image to text)
(more entropy and variables)
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| [https://en.wikipedia.org/wiki/Viscosity Viscosity]
| [https://en.wikipedia.org/wiki/Viscosity Viscosity]
| Pa·s (Pascal second) or P (Poise, 1 Poise is 0.1 Pa.s)
| Pa·s (Pascal second) or P (Poise, 1 Poise is 0.1 Pa.s)
|-
| C, C<sub>p</sub>, C<sub>V</sub>
| [https://en.wikipedia.org/wiki/Heat_capacity#Metrology Heat capacity], general, at constant pressure, at constant volume.
| J.K<sup>-1</sup> (Joule per Kelvin)
|-
| G
| [https://en.wikipedia.org/wiki/Gibbs_free_energy Gibbs free energy]
| J (Joule)
|-
|-
| H
| H
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|[https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Ideal_gas_approximation_at_low_temperatures Clausius-Clapeyron relation]
|[https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Ideal_gas_approximation_at_low_temperatures Clausius-Clapeyron relation]
|Relation between the pressure, latent heat of vaporization and temperature of a vapour at two temperatures (approximation, at low temperatures).
|Relation between the pressure, latent heat of vaporization and temperature of a vapour at two temperatures (approximation, at low temperatures).
|-
|style="background:white"| {{SERVER}}/images/formulas_mirror/Qdefinition.png
|Definition of [https://en.wikipedia.org/wiki/Heat#Path-independent_examples_for_an_ideal_gas Heat] for an ideal gas.
|The heat required to change the temperature of a system from an initial temperature T<sub>0</sub>, to a final temperature, T<sub>f</sub>.
|-
|-
|style="background:white"| {{SERVER}}/images/formulas_mirror/QeqmL.png
|style="background:white"| {{SERVER}}/images/formulas_mirror/QeqmL.png
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|ΔS<sub>universe</sub> = ΔS<sub>surroundings</sub> + ΔS<sub>system</sub>
|ΔS<sub>universe</sub> = ΔS<sub>surroundings</sub> + ΔS<sub>system</sub>
|Entropy variation as a whole.
|Entropy variation as a whole.
|Entropy variation of a system is generally compensated by the inverse variation of the surroundings not including losses.
|Entropy variation of a system is generally compensated by the inverse variation of the surroundings, not including losses.
|-
|-
|style="background:white"| {{SERVER}}/images/formulas_mirror/gibbs.png
|style="background:white"| {{SERVER}}/images/formulas_mirror/gibbs.png
|[https://en.wikipedia.org/wiki/Gibbs_free_energy Gibbs free energy] / Free enthalpy
|[https://en.wikipedia.org/wiki/Gibbs_free_energy Gibbs free energy] / Free enthalpy
|Useful work obtainable from a system at isobaric and isothermal conditions.
|Useful work obtainable from a system at isobaric and isothermal conditions. Since H is U + pV, it can be replaced in the equation, making G = H - TS.
|-
|style="background:white"| {{SERVER}}/images/formulas_mirror/deltaG.png
|[https://en.wikipedia.org/wiki/Gibbs_free_energy Gibbs free energy] variation.
|This derivation is only valid at constant temperature.
|}
|}

Revision as of 23:29, 10 April 2012

Resources on physics related to aerodynamics

The List of elementary physics formulae on wikipedia is useful.

List of variables

Variable Meaning Unit (SI)
γ (gamma) Surface tension N.m-1 (Newton per meter)
μ (mu) or η (eta) Viscosity Pa·s (Pascal second) or P (Poise, 1 Poise is 0.1 Pa.s)
C, Cp, CV Heat capacity, general, at constant pressure, at constant volume. J.K-1 (Joule per Kelvin)
G Gibbs free energy J (Joule)
H Enthalpy: total energy of a thermodynamic system. J (Joule)
ΔHvap or L Vaporization heat or Latent heat of vaporization: energy required to vaporize a mole of liquid at a given temperature. J.mol-1 (Joule per mole)
Q Amount of Heat J (Joule)
T Temperature K (Kelvin)
S Entropy J.K-1 (Joule per Kelvin)
U Internal energy of a system (see first law of Thermodynamics below) J (Joule)
V Volume m3 (cubic meter)
W Work: mechanical constraints on the system. J (Joule)
n Quantity of matter mol (mole)
p Pressure Pa (Pascal)

List of constants

Constant Meaning Value Unit (SI)
NA or N Avogadro constant, number of atoms or molecules in a mole. 6.02214129.1023 mol-1
R ideal gas constant 8.3144621 J.K−1.mol−1
kB or k Boltzmann constant, gas constant R divided by Avogadro number. 1.3806488.10-23 J.K-1

List of equations

Equation Name Meaning
pvnrtk.png Ideal gas equation Relation between properties of an ideal gas (state equation). k is kB.
clausius-clapeyron.png Clausius-Clapeyron relation Relation between the pressure, latent heat of vaporization and temperature of a vapour at two temperatures (approximation, at low temperatures).
QeqmL.png Heat at state change for an ideal gas. The heat required to change the state of a some matter, L being the latent heat. Delta H equals Q only when pressure is constant (isobaric).
dUeqdQmindW.png First law of Thermodynamics Variations of internal energy of a system between two states is the sum of the received heat and work (minus the given work).
enthalpy.png Enthalpy Total amount of energy of a system, defined as the sum of the internal energy U and pressure * volume.
workExpand.png Work of gas expansion. Work done by expanding an ideal gas.
entropy_dueqtdsmpdv.png Entropy Internal energy related to entropy variation for a closed system in thermal equilibrium (fundamental thermodynamic relation).
ΔSuniverse = ΔSsurroundings + ΔSsystem Entropy variation as a whole. Entropy variation of a system is generally compensated by the inverse variation of the surroundings, not including losses.
gibbs.png Gibbs free energy / Free enthalpy Useful work obtainable from a system at isobaric and isothermal conditions. Since H is U + pV, it can be replaced in the equation, making G = H - TS.
deltaG.png Gibbs free energy variation. This derivation is only valid at constant temperature.