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. Application: free-surface flows, stratified flows, cavitation, filling, sloshing, the motion of large bubbles in a liquid, the motion of liquid after a dam break, the prediction of jet breakup (surface tension), and the steady or transient tracking of any liquid-gas interface.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.In this approach, a single set of momentum equations is shared by the fluids, and the volume fraction of each of the fluids in each computational cell is tracked throughout the domain.To take advantage of each method a combined level set volume of fluid (CLSVOF) approach is used However the LS approach is mass conservative. To overcome this, level set (LS) function is used to get a sharp interface. The volume of fluid (VOF) method is mass conservative but interface is not sharp (diffusive) and surface tension is not correctly accounted.A mathematical function is used at the interface to discriminate two adjacent phases.It is designed for t wo or more immiscible fluids where the position of the interface between the fluids is necessary.This approach is u sedВ for a fixed Eulerian mesh.1) Interface Capturing Method (VOF/LS/CLSVOF):

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