January 1970
·
38 Reads
What is this page?
This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.
Publications (18)
October 1969
·
44 Reads
·
71 Citations
Alternating-direction implicit (ADI) time-differencing approximations are developed for the two-dimensional neutron group-diffusion equations. These methods are analyzed for accuracy and stability relative to the implicit-difference approach used in the TWIGL program. It is shown that for model problems (bare homogenous reactors with constant material properties) the ADI method is as accurate as the TWIGL method and much faster computationally. However, several numerical comparisons show that the ADI approach is asymptotically unstable for non-model problems unless extremely small time-steps are used. Such comparisons show the ADI methods (considered in this paper) to be inferior to the TWIGL method for realistic reactor-dynamic problems. A variant on the ADI scheme (ADI-B²) is developed and for a class of delayed supercritical problems shown to be potentially superior to all methods considered.
September 1969
·
5 Reads
November 1968
·
5 Reads
·
4 Citations
Nuclear Science and Engineering
The ability to obtain accurate solutions to time-dependent group diffusion problems by simultaneously synthesizing in both the z and t dimensions is demonstrated numerically. The potential of the combined space-time synthesis method becomes apparent from several comparisons of synthesis solutions with exact (in a finite difference sense) two-group, two-dimensional, time-dependent diffusion solutions for two different reactor geometries.
September 1968
·
9 Reads
February 1968
·
2 Reads
·
3 Citations
Nuclear Science and Engineering
January 1968
·
9 Reads
·
8 Citations
Nuclear Science and Engineering
An exploration is made into a method for using reciprocal variational problems to develop figures of merit for approximate solutions of diffusion problems. The theory of the reciprocal problems is described in both a continuous and discrete context. Connections with the method of Slobodyansky are discussed. A strategem is presented for extending the method to the (non-self-adjoint) group-diffusion case. Limitations of the method are discussed and numerical examples given. It is concluded that the method is useful in one-, two-, and perhaps in small three- dimensional problems but is probably computationally not practical for full-blown, detailed, three-dimensional calculations.
January 1968
·
1 Read
January 1968
·
74 Reads
·
24 Citations
January 1968
·
4 Reads
Citations (5)
... The thermal resistance of heat transfer through an inhomogeneous anisotropic solid between surface sections experiencing convective heat exchange with the ambient medium can be estimated with the use of a mathematical model describing the steady-state temperature distribution in the solid. A transformation of this mathematical model permits constructing a dual variational statement of the steady-state thermal conduction problem, which contains two functionals dual to each other (one to be minimized and the other to be maximized) [6][7][8][9] attaining the same extremal value on the actual solution of the problem. The desired thermal heat transfer resistance can be expressed via this value. ...
- Citing Article
January 1968
Nuclear Science and Engineering
... Therefore both of the methods approximate reality in some sense because the effects of thermal-hydraulic feedback and direct operator control action have been neglected. It is possible to include passive feedback effects in modal stability analyses ( [1,4,6], for example), but it is impossible to include operator-driven control actions in the type of linearized analysis presented here. Pragmatically, the best such an analysis can offer is the prediction of transient behavior in regimes where nonlinear feedback or external actions are not significant. ...
- Citing Article
August 1966
Nuclear Science and Engineering
... Rapid transients of reactor power in large reactors, caused by sudden reactivity insertion, have strong space-dependent effect associated with them and in such cases the point reactor model alone cannot predict the true behaviour of reactor transients. The inadequacy of the point-reactor model for the analysis of large thermal reactor transients was numerically demonstrated by Yasinsky and Henry (1965). ...
- Citing Article
June 1965
Nuclear Science and Engineering
... Detailed group cross-sections are given in Table 5. Calculated eigenvalues compared with reference values and PRIDE code are given in Table 6. Figure 7 and Figure 8 show fast and thermal flux comparison along the diagonal of the core with the reference flux profile. 28 The results are in close agreement with a relative error of less than 0.05%. ...
- Citing Article
January 1968
... And we will propose corresponding evaluation criteria to verify the validity of numerical results in Section 4.1. Further, we will give details, numerical solutions and related evaluation results of one-dimensional problem [38], two-dimensional and three-dimensional TWIGL problem [39], and two-dimensional and three-dimensional IAEA problem [34] with different residual loss function applied. As mentioned earlier, we have a total of three training point sets X Res , X Bou , X Int for our training points. ...
- Citing Article
October 1969