Pre-processors

GETNOD Reads and echo prints nodal coordinates fonnatting should match the output generated by the pre-processor. 

A pre-processor program should usually be used to generate the following data lines... 

The pre-processor consists of inputting a problem into a CFD program using a friendly interface, which is transformed into a suitable format for the solver. The user activities at this stage involve ... 

Commercially available CFD codes have three main elements in common. Firstly, the pre-processor enables the user to define the geometry, which is often referred to as the computational domain or flow domain of the problem, for... 

The hypothesis of a normal distribution is a strong limitation that should be always kept in mind when PCA is used. In electronic nose experiments, samples are usually extracted from more than one class, and it is not always that the totality of measurements results in a normally distributed data set. Nonetheless, PCA is frequently used to analyze electronic nose data. Due to the high correlation normally shown by electronic nose sensors, PCA allows a visual display of electronic nose data in either 2D or 3D plots. Higher order methods were proposed and studied to solve pattern recognition problems in other application fields. It is worth mentioning here the Independent Component Analysis (ICA) that has been applied successfully in image and sound analysis problems [18]. Recently ICA was also applied to process electronic nose data results as a powerful pre-processor of data [19]. 

Software for NMR applications is now in widespread use and it is therefore important that such packages work well not only in more traditional chemical shift, relaxation or resonance applications but in the more recent context as potential pre-processors of imaging data. 

P 28] A 3-D solid model of the cross-shaped micro mixer is meshed to a sufficiently fine scale with brick elements of 2 pm for the simulations [71]. Simulation results were intended at very short time scales, e.g. in intervals of 50 ps, to verify the mixing patterns at the initial state after application of pressure. The numerical values of the mass fraction are taken to give quantitative measures of the mixing efficiency. The pre-processor fluidics solver and post-processor of ConventorWare were used for the simulations. The software FLUENT 5 was used for verification of these results, since the former software is so far not a widely established tool for fluid dynamic simulation. 

Baklanov A, Clappier A, Fay B, Joffre S, Karppinen A, 0degard V, Slprdal LH., Sofiev M, Sokhi RS, Stein A (2005) Improved interfaces and meteorological pre-processors for urban air pollution models. In Finardi S (ed) Deliverable 5.2-3 of the EC FUMAPEX project, Milan, Italy, 55 pp... 

Experiments have been performed to address the error made by the pre-processor in AirQUIS. Figure 13.2 shows the resulting NO2 forecasts from AirQUIS using dispersion parameters calculated by the pre-processor compared to AirQUIS using dispersion parameters calculated by the meteorological model MM5. 

Both in the pre-processor and in MM5 the dispersion parameters are calculated using MOST. The difference is, therefore, due to a time step update of the parameters going into the parametrization scheme rather than an hourly update in the preprocessor. The figure shows that this difference has very small impact on the results. 

Fig. 13.2 NO2 forecasts from AirQUIS using surface fluxes from pre-processor (black) and from MM5 (blue) compared to observations (red) (from Slprdal and 0degaard, 2005)...

Tel. 49-9131-85-7335, e-mail gedeck pctc.chemie.uni-erlangen.de MOPAC Pre-Processor constructs Z-matrix from structural fragments. 

Although in many commercially available CFD codes, some capabilities of pre-and post-processors are bundled up with the solver, it will be useful to discuss the CFD tools by classifying them in the stated three categories. It is important to mention here that it is more useful to compare CFD codes based on underlying technological issues rather than based on their features . The main technological issues in pre-processors, solvers and post-processors are listed in Table 8.2, and are discussed in the following sub-sections. 

This category usually includes geometry modeling and grid generation tools. In some cases, specification of the required information about the system under consideration and the numerical technique used can also be specified using pre-processors. Some... 

General Purpose CFD Codes FLUENT Pre-processors preBFC, GAMBIT, Tgrid Main codes Fluent4.5, FluentS, FIDAP, Rampant, Nekton, MixSim Post-processors in-built in above codes, Flpost www.fluent.com... 

AEA Technology Pre-processors CFX-Build Main codes CFX4, CFX5, CFX-ProMixus Post-processors CFX-Visualize www.aeat.com/cfx... 

AVL Pre-processor FAME Main codes FIRE, SWIFT Post-processor in-built in above codes www.avl.com... 

CFDRC Pre-processor CFD-GEOM Main code CFD-ACE6, CFD-ACE (U) Post-processors CFD-VIEW www.cfdrc.com... 

Stand-alone Pre-processors Pointwise Gridgen www.pointwise.com... 

TABLE 8.2 Key Issues for Evaluating CFD Pre-processors, Solvers and Post-processors ... 

Grid types import from different pre-processors co-located/ staggered (un) structured Automatic grid refinement tools, addition of grid elements Geometry modifications (change scale/cell type etc.) without re-meshing... 

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