摘要:

AbstractThe bifurcation of confined swirling flows was numerically investigated by employing both thek‐ϵ and algebraic stress turbulence models. Depending upon the branch solution examined, dual flow patterns were predicted at certain swirl levels. In the lower‐branch solution which is obtained by gradually increasing the swirl level from a low‐swirl flow, the flow changes with increasing swirl number from the low‐swirl flow pattern to a high‐swirl flow pattern. In the upper‐branch solution which is acquired by gradually decreasing the swirl level from a high‐swirl flow, on the other hand, the flow can maintain itself in the high‐swirl flow pattern at the swirl levels where it exhibits the low‐swirl flow pattern in the lower branch. The bifurcation of confined swirling flows was predicted with either thek‐ϵ model or the algebraic stress model being employed. Both thek‐ϵ and algebraic stress models result in comparable and sufficiently good predictions for confined swirling flows if high‐order numerical schemes are used. The reported poor performance of thek‐ϵ model was clarified to be mainly attributable to the occurrence of the bifurcation and the use o

ISSN:0271-2091    

DOI:10.1002/fld.1650191102

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractAn improved pressure‐based method has been applied to predict the two‐dimensional instability analysis of liquid‐fuelled rocket engines. This method is non‐iterative for transient flow calculations and applicable to all‐speed flows. Validation cases include the shock‐tube problem, the blast flow field and unsteady spraycombusting flows. Computations for the combustion instability analysis were carried out for various combustion parameters such as spray initial conditions and combustor geometries. Unsteady behaviours of the stable and unstable spray flame fields and effects of acoustic oscillations on the fuel droplet vaporization and combustion process are studied in detail. The present numerical model successfully demonstrates the capability of predicting combustion instability as well as fast transient compressible flows at

ISSN:0271-2091    

DOI:10.1002/fld.1650191103

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of the highest‐order ((N– 1)th‐order) Lagrangian interpolation Polynomial for the approximation of the exact solution in the backward characteristics scheme withNnodes is inefficient owing to the excessive number of terms in the polynomial. New schemes based on a combination of lower‐order polynomials to approximate the exact solution are developed, with the relative weighting of the polynomials determined by Fourier mode analysis. With the addition of a flux limiter and a modified discriminator, the resulting schemes are oscillation‐free, highly accurate, efficient and more cost‐effective as compared with those schemes using the highest‐order Lagrangi

ISSN:0271-2091    

DOI:10.1002/fld.1650191104

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractPredictions for two‐dimensional, steady, incompressible flows under both laminar and turbulent conditions are presented. The standardk‐ϵ turbulence model is used for the turbulent flows. The computational method is based on the approximate factorization technique. The coupled approach is used to link the equations of motion and the turbulence model equations. Mass conservation is enforced by either the pseudocompressibility method or the pressure correction method. Comparison of the two methods shows a superiority of the pressure correction method. Second‐ and fourth‐order artifical dissipation terms are used in order to achieve good convergence and to handle the turbulence model equations efficiently. Several internal and external test cases are investigated, including attached and separat

ISSN:0271-2091    

DOI:10.1002/fld.1650191105

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA fully discrete methodology is investigated from which two‐level, explicit, arbitrary‐order, conservative numerical schemes for a model parabolic equation can be derived. To illustrate this, fully discrete three‐, five‐, seven‐ and nine‐point conservative numerical schemes are presented, revealing that a higher‐order scheme has a better stability condition. A method from which high‐order numerical schemes for a scalar advection‐diffusion equation can be developed is discussed. This method is based on high‐order schemes of both the advection and

ISSN:0271-2091    

DOI:10.1002/fld.1650191106

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650191107

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650191108

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650191109

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY