Computer domain

Each of these and other phenomena could, by themselves, benefit from in-depth examination. This article focuses primarily on those computing technologies that find appHcation in computational domains, especially within computational chemistry. 

There are two feasible ways of handling this problem one is to include some of the outdoor space in the CFD computation domain the other is to calculate the quantities through the interfaces of concern by other methods. Such methods include the use of analytical formulas, e.g., for temperature-difference-driven flow through an opening, or the use of a multizone program. The latter method is illustrated in the following example. - ... 

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... 

Instead of dividing the computation domain into lubrication regions and asperity contact areas, the mixed lubrication model proposed by the present authors assumes that the pressure distribution over the entire domain follows the Reynolds equation ... 

The approach has proven to be advantageous in comparison with the conventional" method. Because the reduced equation is a special form of the Reynolds equation, a full numerical solution over the entire computation domain, including both the hydrodynamic and the contact areas, thus obtained through a unified algorithm for solving one equation system. In this way, both hydrod5mamic and con-... 

Green s function h x) was truncated at the boundary of computation domain. In reality, however, function h x) may possess non-zero values beyond the computation domain. The truncation of h x) will therefore result in errors in the convolution. The error is expected to be minimal at the center of computation domain but increases at the positions close to the border of the domain. 

Discretize the influence coefficient K x) into a series Kj)2N of size 2N in a region whose sides are twice as that of the computation domain. 

Discretize the pressure functionp(x) into a series pi M of size N in the computation domain, and then extend the length of the series pil into a new series pN )2N through zero padding. 

Comparisons of the accuracy and efficiency for three numerical procedures, the direct summation, DC-FFT-based method and MLMI, are made in this section. The three methods were applied to calculating normal surface deformations at different levels of grids, under the load of a uniform pressure on a rectangle area 2a X 2fo, or a Hertzian pressure on a circle area in radius a. The calculations were performed on the same personal computer, the computational domain was set as -1.5a=Sx 1.5a and -1.5a=Sy 1.5a, and covered... 

Complete specification of the problem requires that boundary conditions be imposed at each end of the computational domain. At y = 0 we have... 

Via a passive scalar method [6] where or, denotes the volume fraction of the i-th phase, while T, represents the diffusivity coefiBcient of the tracer in the i-th phase. The transient form of the scalar transport equation was utilized to track the pulse of tracer through the computational domain. The exit age distribution was evaluated from the normalized concentration curve obtained via measurements at the reactor outlet at 1 second intervals. This was subsequently used to determine the mean residence time, tm and Peclet number, Pe [7]. 

Figure 2.21 Computational domain of a multichannel reactor for methanol reforming.

TeGrotenhuis et al. studied a counter-current heat-exchanger reactor for the WGS reaction with integrated cooling gas channels for removal of the reaction heat. The computational domain of their 2-D model on the basis of the finite-element method... 

The physical properties of the particle are the same as FCC particles. The simulation is conducted using a 140 x 140 x 200 rectangular mesh covering a 7 mm x7mmx 10 mm computational domain. Both the 3-D images and the temperature field are shown in this figure. 

The numerical solution of the discretized model equations evolves through a sequence of computational cycles, or time steps, each of duration St. For each computational cycle, the advanced ( +l)-level values at time t + St of all key variables have to be calculated for the entire computational domain. This calculation requires the old n-level values at time t. which are known from either the previous computational cycle or the specified initial conditions. Then each computational cycle consists of two distinct phases ... 

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