adaptive mesh refinement (AMR) نازکش ِ نیاوشی ِ بانچه nâzokeš-e niyâveši-ye bâncé
*Fr.: raffinement de maillage adaptatif*
A type of → *algorithm* that dynamically achieves high
→ *resolution* in localized regions of multidimensional
→ *numerical simulation*s.
AMR provides a higher → *accuracy* solution at
lower costs, through an automatically → *optimal*
distribution of → *grid* points for the
computation region. It relies on locally refined mesh or mesh
patches to increase the resolution of an underlying
coarse mesh only where needed.
It can alleviate some of the complexities of the generation of high
quality grid and reduce the number of → *iteration*s of
"trial-and-error" between the grid generation and solution
required for tailoring the grid to the specification of a
problem. Thus, it can offer orders of magnitude saving in
computational and storage costs over an equivalent uniformly refined
mesh. AMR was originally developed for → *inviscid*,
→ *compressible flow* (Berger et al., 1984,
Adaptive Mesh Refinement for Hyperbolic Partial Differential
Equations. J. Comp. Phy., 53, 484). It
has been extended to solve → *Navier-Stokes equation*s,
time dependent problems and more. Several
AMR techniques have been developed and applied to compressible flow fields to capture
characteristics at the strong gradient or discontinuous regions requiring higher space resolution,
such as regions involving → *shock wave*s,
vortices (→ *vortex*), and
→ *wake*s
(see, e.g., Qingluan Xue, "Development of Adaptive Mesh Refinement Scheme and
Conjugate Heat Transfer Model for Engine Simulations" (2009), Iowa State Univ., Graduate
Theses and Dissertations, Paper 10678).
See also → *Smoothed Particle Hydrodynamics*. → *adaptive*; → *mesh*;
→ *refinement*. |

extreme adaptive optics نوریک ِ نیاوشی ِ استوم nurik-e niyâveši-ye ostom
*Fr.: optique adaptative extrême*
An → *adaptive optics system* with
high-contrast imaging and spectroscopic capabilities.
Extreme adaptive optics systems enable the detection of
faint objects (e.g., → *exoplanet*s)
close to bright sources that would otherwise overwhelm
them. This is accomplished both by increasing the peak intensity of
point-source images and by removing light scattered by the atmosphere
and the telescope optics into the → *seeing disk*. → *extreme*; → *adaptive*;
→ *optics*. |