aerodynamics havâtavânik Fr.: aérodynamique The science that is concerned with the study of the → motion of → air and other gaseous → fluids and with the → forces acting on bodies moving through such fluids. |
astrodynamics axtartavânik Fr.: astrodynamique The science dealing with the motion of satellites, rockets, and spacecrafts. It uses the principles of celestial mechanics. Astrodynamics, from → astro- "star" + → dynamics. |
chromodynamics rangtavânik Fr.: chromodynamique A → quantum field theory of the → interaction of → quarks possessing a distinctive property called → color, in which the quarks exchange → gluons in a manner that is analogous to the interaction of → charged particles in → electrodynamics. |
dynamics tavânik Fr.: dynamique The branch of → mechanics that explains how particles and systems move under the influence of forces. |
electrodynamics barqâtavânik Fr.: électrodynamique The phenomena, science, and applications of moving electric charges, as contrasted with → electrostatics. More specifically, the branch of physics concerned with the → interaction of → electric currents with → magnetic fields and → electric fields or with other electric currents. |
first law of thermodynamics qânun-e naxost-e garâtavânik Fr.: première loi de la thermodynamique The total energy of a → closed system is constant. This means that energy can be changed from one form to another, or transferred from one system to another, but it cannot be created or destroyed. A mathematical formulation of the first law is: δQ = δU + δW, where δQ is the heat transferred to the system, δU the change in internal energy (resulting in a rise or fall of temperature), and δW is the work done by the system. → first; → law; → thermodynamics. |
fluid dynamics tavânik-e šârehâ Fr.: dynamique des fluides The branch of → fluid mechanics that deals with the movement of gases and liquids. |
galactic dynamics tavânik-e kakhešâni Fr.: dynamique galactique The study of the → motions of the → stars, → gas, and → dark matter in a → galaxy to explain the main → morphological and → kinematical features of the galaxy. |
Hamiltonian dynamics tavânik-e Hamilton Fr.: dynamique hamiltonienne The study of → dynamical systems in terms of the → Hamilton's equations. → Hamiltonian function; → dynamics. |
hydrodynamics hidrotavânik Fr.: hydrodynamique The branch of physics dealing with the motion, energy, and pressure of neutral → fluids. |
Lagrangian dynamics tavânik-e lâgrânži Fr.: dynamique lagrangienne A reformulation of → Newtonian mechanics in which dynamical properties of the system are described in terms of generalized variables. In this approach the → generalized coordinates and → generalized velocities are treated as independent variables. Indeed applying Newton's laws to complicated problems can become a difficult task, especially if a description of the motion is needed for systems that either move in a complicated manner, or other coordinates than → Cartesian coordinates are used, or even for systems that involve several objects. Lagrangian dynamics encompasses Newton dynamics, and moreover leads to the concept of the → Hamiltonian of the system and a process by means of which it can be calculated. The Hamiltonian is a cornerstone in the field of → quantum mechanics. → Lagrangian; → dynamics. |
laws of dynamics qânunhâ-ye tavânik Fr.: lois de dynamique The three basic laws of → dynamics which were first formulated by Isaac Newton in his classical work "Mathematical Principles of Natural Philosophy" published in 1687. → Newton's first law of motion; → Newton's second law of motion; → Newton's third law of motion. |
magnetohydrodynamics (MHD) meqnâtohidrotavânik Fr.: magnétohydrodynamique The dynamics of an ionized plasma in the non-relativistic, collisional case. In this description, charge oscillations and high frequency electromagnetic waves are neglected. It is an important field of astrophysics since plasma is one of the commonest forms of matter in the Universe, occurring in stars, planetary magnetospheres, and interplanetary and interstellar space. From → magneto- + → hydrodynamics. |
MOdified Newtonian Dynamics (MOND) tavânik-e niyutoni-ye vâtarzidé Fr.: dynamique newtonienne modifiée A modification of the Newton's law of gravitation below a critical acceleration of about 1.2 x 10^{-8} cm s^{-2}, where the gravitational force scales as 1/r instead of 1/r^{2}. Originally put forward to describe the rotation curves of galaxies with no need to assume any dark matter, MOND is now tested at larger cosmological scales (Milgrom, M. 1983, ApJ, 270, 365). → modify; → Newtonian dynamics. |
nonlinear dynamics tavânik-e nâxatti Fr.: dynamique non-linéaire Same as → chaos. |
quantum chromodynamics rangtavânik-e kuântomi Fr.: chromodynamique quantique The → quantum field theory that deals with the → strong interaction and the structure of elementary particles in the framework of → quantum theory. The cohesive attraction between the → quarks, that constitute → hadrons, involves the participation of three particles. Each of these particles is assigned a different → color "charge." The existence of these "charges" requires a multiplicity of different messenger particles to communicate the interaction and glue the quarks together. These messengers are called → gluons and there are eight different types. → quantum; → chromodynamics |
quantum electrodynamics (QED) barqâtavânik-e kuântomi Fr.: électrodynamique quantique The → quantum field theory that describes the properties of → electromagnetic radiation and its interaction with electrically charged matter in the framework of → quantum theory. → quantum; → electrodynamics. |
second law of thermodynamics qânun-e dovom-e garmâtavânik Fr.: deuxième loi de la thermodynamique 1) Heat cannot be transferred from a colder to a hotter body without some other effect, i.e.
without → work being done. Expressed in terms of
→ entropy: the entropy of an
→ isolated system tends toward a maximum and its
available energy tends toward a minimum. → second; → law; → thermodynamics. |
Smoothed Particle Hydrodynamics (SPH) hidrotavânik-e zarrehâ-ye hamvâridé Fr.: hydrodynamique des particules lissées A numerical method for modeling → compressible hydrodynamic flows, which uses particles to simulate a continuous fluid flow. Because the system of hydrodynamical basic equations can be analytically solved only for few exceptional cases, the SPH method provides a numerical algorithm to solve systems of coupled → partial differential equations for continuous field quantities. The main advantage of the method is that it does not require a computational grid to calculate spatial → derivatives and that it is a Lagrangian method, which automatically focuses attention on fluid elements. The equations of motion and continuity are expressed in terms of ordinary differential equations where the body forces become classical forces between particles. This method was first independently developed by Lucy (1977, AJ 82, 1013) and Gingold & Monaghan (1977, MNRAS 181, 375). Smoothed Particle Hydrodynamics, first used by Gingold & Monaghan (1977); → smooth; → particle; → hydrodynamics. |
statistical thermodynamics garmâtavânik-e âmâri Fr.: thermodynamique statistique Same as → statistical mechanics. → statistical; → thermodynamics. |