摘要:

AbstractComputations of a confined coaxial swirling jet are carried out using a standard two‐equation (k‐ε) model and two modifications of this model based on Richardson number corrections of the length scale (ε) governing equation. To avoid any uncertainty involved in the setting up of inlet boundary conditions, actual measurements are used at the inlet plane of this calculation domain. The results of the numerical investigation indicate that thek‐ε model is inadequate for the predictions of confined swirling flows. Although marginal improvement of the flow predictions can be achieved by these two corrections, both cannot be judged sati

ISSN:0748-8025    

DOI:10.1002/cnm.1630020402

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn efficient program is developed for selecting subminimal cycle bases of graphs. In this program an expansion process is used and independent cycles of minimal lengths are generated. The independence is provided by restricting the increase of Betti number by unity in each step of the process.

ISSN:0748-8025    

DOI:10.1002/cnm.1630020403

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractLeast squares smoothing is applied to thermal strain calculation. The smoothing procedure eliminates apparent errors in thermal stresses due to mismatch of thermal and mechanical strain orders which facilitates direct evaluation of results. General procedures are developed and demonstrated for two‐dimensional isoparametric elements. Examples serve to illustrate the effectiveness of the smoothing procedur

ISSN:0748-8025    

DOI:10.1002/cnm.1630020404

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractHeat exchanges affect the gasification process particularly of thin coal layers. Further experimental evidence is presented that heat lost to the surroundings is partly reintroduced into the reaction zone (heat recuperation). This heat recuperation effect has now been quantified by the finite element calculation of the transient temperature distribution. The calculated values show good agreement with the experimental data. The calculation shows, moreover, that the temperature rise in the coal bed above the adiabatic level must be partly attributed to the heat recuperation effect. Therefore, heat recuperation has a significant effect on the gasification reactions.

ISSN:0748-8025    

DOI:10.1002/cnm.1630020405

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents a method for solving vibration problems of a plate with irregular shape lying on an elastic foundation in consideration of effects of masses of foundation. For the foundation, the equation of motion of longitudinal vibrations of a solid is utilized, and the solutions of both the foundation and the plate are joined together by use of the conditions of continuity between the plate and the foundation. The analysis uses the Fourier expansion collocation method given by Nagaya to satisfy the irregular boundary conditions. Numerical calculations have been carried out for general polygonal plates on elastic foundations. The results for the plate on Winkler's foundation are also given to compare both results. It is clarified that there are some discrepancies between the present result which includes foundation inertias and that of Winkler's foundation.

ISSN:0748-8025    

DOI:10.1002/cnm.1630020406

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA boundary smoothing technique for control of hourglassing deformation in quadrilateral and hexahedral finite elements is described. In this technique, supplemental forces are applied to lines of nodes along the boundary to eliminate length and angle changes associated with hourglassing. The main advantage of this technique is that it can be applied locally to a small number of nodes along the boundary rather than globally to all elements as is the case with other control techniques, thereby reducing the additional computational expense required for hourglassing control. This reduction can be especially significant in three‐dimensional problems. An example problem consisting of a square plate subjected to a step pressure is used to demonstrate the efficacy of the techniqu

ISSN:0748-8025    

DOI:10.1002/cnm.1630020407

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractOrder‐of‐magnitude deletion of the stream‐wise diffusion terms leads to a reduced form of the Navier–Stokes equations. Solving the reduced equations for internal flows with single‐sweep marching algorithms requires a severe minimum stream‐wise step‐size to avoid unstable solutions. This behaviour is shown to be predominantly due to a single term in the cross‐stream momentum equation,uvx, which introduces a strong elliptic character into the equations. An order‐of‐magnitude deletion of this term reduces the minimum stream‐wise step‐size sufficiently for accurate solutions to be obtained. Further reduction of the transverse momentum equation on an order‐of‐magnitude basis removes all cross‐stream velocity derivatives and completely eliminates the minimum stream‐wise step‐size condition for bot

ISSN:0748-8025    

DOI:10.1002/cnm.1630020408

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractNine different algorithms for the acceleration of vector sequences are considered. All have the property that, in one dimension, they reduce to the standard Aitken Δ2process. Different rules for deciding when to accelerate are also discussed. Theoretical and practical results show a wide range of performance, but it is shown that certain methods can be recommended for use

ISSN:0748-8025    

DOI:10.1002/cnm.1630020409

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractHarmonic decomposition is applied to the shallow water equations, thereby creating a system of equations for the amplitude of the various tidal constituents and for the residual motions. The resulting equations are elliptic in nature, are well posed and in practice are shown to be numerically well‐behaved. There are a number of strategies for choosing elements: the two extremes are to use a few high‐order elements with continous derivatives, or to use a large number of simpler linear elements. In this paper simple linear elements are used and prove effect

ISSN:0748-8025    

DOI:10.1002/cnm.1630020410

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630020411

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY