Grid distances

Gaussian electrostatic evaluations of the Carbo index provided better results than grid-based calculations, while in the case of shape the grid-based evaluations seemed to be more suitable. Grid distances of 0.05 nm for shape and 0.2 nm for electrostatics were sufficient to give a satisfactory description of the biological data. 

T170 resolution roughly corresponds to 80-km grid resolution. Increase in the T number corresponds to a proportional decrease in grid distance. 

Hence, each grid induces a characteristic flame acceleration factor, which depends on the shape parameter of the grid, but is fairly independent of the chosen mixture composition. In any case, this factor increases with the reduced grid distance x/d as shown in Fig. 9. Whether this finding will prove true also for other fuels (propane, butane, hydrogen, etc.) will be investigated in the near future. 

The conventional PCB constructions today cannot handle any grid arrays with pitches below 0.020 in, while some flip-chip ball grid arrays go below 0.010-in pitch. In cases when grid distances of the area terminations are below 0.50 mm (0.040 in), special redistribution layers are frequently used, which distribute signals to the conventionally made PTHs in supporting MLB. 

A sufficiently large box is positioned around the molecules and a grid distance is defined. Different atomic probes, e.g., a carbon atom, a positively or negatively charged atom, a hydrogen bond donor or acceptor, or a lipophilic probe, are used to calculate field values in each grid point, i.e., the energy... 

A distance of 2 A seems to be an extremely wide grid distance if one considers that even a few tenths of an A are responsible for the difference between van der Waals attraction and strong repulsion between two atoms. However, this distance is dictated by the exponential increase of the computational effort if smaller grid distances are chosen. 

The fineness of the grid pattern, called resolution, is quantified in terms of pixels per linear distance. Common practice for commercial quaUty images assumes that photographic images can be reproduced accurately using about 300 pixels per inch (120 pixels/cm). 

When a coarse grid is used, wall functions are used for imposing boundary conditions near the walls (Section 11.2.3.3). The nondimensional wall distance should be 30 < y < ]Q0, where y = u,y/p. We cannot compute the friction velocity u. before doing the CFD simulation, because the friction velocity is dependent on the flow. However, we would like to have an estimation of y" to be able to locate the first grid node near the wall at 30 < y < 100. If we can estimate the maximum velocity in the boundary layer, the friction velocity can be estimated as n, — 0.04rj, . . After the computation has been carried out, we can verify that 30 nodes adjacent to the walls. 

Vo is given in A electron charge units, r is the closest distance (in A) between the grid points to the indicated solute atom. 

---