Nsel_: number of transmitted rays from the release feature to the detector.

The following variables are defined by an instance of the Ray Detector feature with the feature tag : The feature provides convenient expressions that can be used in the Filter attribute of the Ray Trajectories plot, which allows only the rays that reach a specified set of domains or boundaries to be visualized. It is possible to count all rays or only those rays released by a specific physics feature. Such quantities include the number of rays transmitted and the transmission probability, or the ratio of the number of transmitted rays to the number of released rays. The Ray Detector feature is a domain or boundary feature that provides information about rays arriving on a set of selected domains or surfaces from a release feature. For example, when rays propagate through graded-index media, the ribbons can be oriented normal to or parallel with the plane containing the curved ray paths.ДЄs the number of extra time steps in the trajectory plot is increased, the times at which each ray bounces off the wall can be seen more clearly. You can specify the orientation and thickness of the ribbon. It is now possible to render ray paths as ribbons in the Ray Trajectories plot. Even though the boundary is a straight edge, the rays increase in intensity after being reflected because the boundary is treated as a surface of revolution for the purpose of computing wavefront curvatures. The color expression shows the ray intensity. The axis of symmetry is shown as a solid red line. Specular reflection for a plane wave in a 2D axisymmetric model. When using one of these dedicated release features, a built-in option is available to release rays in an anisotropic hemisphere such that each ray subtends approximately the same solid angle in 3D.

In addition, dedicated release features are now available to release rays from edges, points, or at specified coordinates along the axis of symmetry. This leads to more realistic calculations of ray intensity in 2D axisymmetric models. In other words, the principal radius of curvature associated with the azimuthal direction is computed for all rays.

When computing ray intensity in 2D axisymmetric models, the wavefront associated with the propagating ray is now treated as a spherical or ellipsoidal wave instead of a cylindrical wave (which is only an appropriate simplification in true 2D models). Improved Ray Tracing in 2D Axisymmetric Geometries Histogram of the polar angles in the isotropic and Lambertian distributions. You can specify directions for the photometric horizontal and photometric zero, which indicate the orientation of the lamp according to IES standards. When the photometric data file is imported into a model, it generates a set of functions that are used to initialize the ray intensity and power as a function of the initial ray direction. To use this feature, select Photometric Data Import for the Intensity initialization in the Total Source Power section of the Release from Grid node. ies file extension, the standard photometric data file format of the Illuminating Engineering Society of North America (IESNA). The Photometric Data File feature supports the. It is possible to specify nonuniform distributions of ray intensity and power by importing photometric data files into a ray optics model. The rays passing through the lens with a shorter focal length decrease in intensity more rapidly past the focal point, so they are terminated by the _Ray Termination_ feature, while the rays passing through the lens with a longer focal length continue to propagate. *Rays propagating through two convex lenses with focal lengths of 200 mm (top) and 100 mm (bottom). This feature can be employed to avoid using excessive computational resources on rays that have become attenuated due to the presence of absorbing media and rays that have extremely low intensity due to interaction with curved surfaces.

Beyond geometrical constraints, rays can be terminated if their intensity or power becomes smaller than a specified threshold, or if they stray too far from the model geometry. You can use the Ray Termination feature to discard unnecessary information about the ray paths and remove clutter from the trajectory plots. The rays can be terminated as they exit a bounding box, which can be based on the geometry or user-defined spatial extents. The new Ray Termination feature can be used to annihilate rays without requiring them to stop at a boundary. See all of the Ray Optics Module updates in more detail below. For users of the Ray Optics Module, COMSOLВ Multiphysics В® version 5.3 brings a new Ray Termination feature to eliminate unnecessary rays, functionality to import photometric data, and a new simulation app for designing a solar dish receiver.

Comsol 5.3 released ate