Hybrid grid generation for viscous flow simulations in complex geometries

Abstract

In this paper, we present a hybrid grid generation approach for viscous flow simulations by marching a surface triangulation on viscous walls along certain directions. Focuses are on the computing strategies used to determine the marching directions and distances since these strategies determine the quality of the resulting elements and the reliability of the meshing procedure to a large extent. With respect to marching directions, three strategies featured with different levels of efficiencies and robustness performance are combined to compute the initial normals at front nodes to balance the trade-off between efficiency and robustness. A novel weighted strategy is used in the normal smoothing scheme, which evidently reduces the possibility of early stop of front generation at complex corners. With respect to marching distances, the distance settings at concave and/or convex corners are locally adjusted to smooth the front shape at first; a further adjustment is then conducted for front nodes in the neighbourhood of gaps between opposite viscous boundaries. These efforts, plus other special treatments such as multi-normal generation and fast detection of local/global intersection, as a whole enable the setup of a hybrid mesher that could generate qualitied viscous grids for geometries with industry-level complexities.

Nanophotonic Color Routing

“…In contrast to the spectral filtering scheme, the light is sorted toward different directions according to its wavelength. Therefore, it provides promising potentials to overcome commercial pigment/dye coloring technique in terms of efficiency, and may open up entirely new design paradigms for various applications including high‐pixel‐density imaging/display, [ 6–11 ] hologram, [ 52–55 ] optical switching, [ 69–72 ] photovoltaics, [ 21–23,73,74 ] on‐chip spectroscopy, [ 13,43–48 ] etc. The content will more focus on the emerging concepts and the technology development trend in particular for the applications in high‐resolution imaging, and discuss the pros and cons of current techniques for the integration with image sensors.…”

“…[ 1,2 ] Coloring techniques in clothes and textiles with a similar mechanism have been developed by dyeing. [ 3–5 ] This spectral filtering technique is central to a diverse set of optical applications including display, [ 6–8 ] color/hyperspectral imaging, [ 9–11 ] spectroscopy, [ 12–15 ] communications, [ 16–19 ] photovoltaics, [ 20–22 ] etc. Any wavelength‐dependent optical effect has the potential for spectral engineering, for example, absorption, [ 13,23 ] diffraction, [ 24–26 ] refraction, [ 27–29 ] and interference [ 30,31 ] as shown in Figure a.…”