摘要:

AbstractThe influence of free stream direction on mixed (natural and forced) convective heat transfer from a circular cylinder is investigated. The cylinder, which has an isothermal surface, is placed with its axis horizontal and normal to the oncoming flow. The free stream direction varies between the vertically upward (parallel flow) and the vertically downward (contraflow) directions. The investigation is based on the time integration of the unsteady, two‐dimensional equations of motion and energy until reaching steady conditions. The study is limited to Reynolds numbers up toRe= 40 and Grashoff numbers ofGr=Re2. The results are compared with the available experimental data and the agreement is satisfactor

ISSN:0271-2091    

DOI:10.1002/fld.1650050102

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractAn adaptive finite element method is developed and applied to study the ozone decomposition laminar flame. The method uses a semidiscrete, linear Galerkin approximation in which the size of the elements is controlled by an integral which minimizes the changes in mesh spacing. The sizes and locations of the elements are controlled by the location and magnitude of the largest temperature gradient. The numerical results obtained with this adaptive finite element method are compared with those obtained using fixed‐node finite‐difference schemes and an adaptive finite‐difference method. It is shown that the adaptive finite element method developed here using 36 elements can yield as accurate flame speeds as fourth‐order accurate, fixed‐node, finite‐difference methods when 272 collocation points are employed in the c

ISSN:0271-2091    

DOI:10.1002/fld.1650050103

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA 3‐D numerical code was developed to solve the irrotational flow of an ideal fluid inside a moving cylindrical container with partitions. The problem is formulated in terms of two Poisson equations, the velocity equation and the pressure equation. These are expressed in terms of finite differences and solved by a procedure of line over relaxation. From the fluid pressure we computed the resultant moment on the container which was then expressed in terms of the equivalent moment of inertia. The code was checked against analytical results of Moiseyev and we found an agreement of 2–5 per cent even for a sparse mesh. We then demonstrated the capability of the code by computing the equivalent moment of inertia for various configurations with full and partial partiti

ISSN:0271-2091    

DOI:10.1002/fld.1650050104

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractFlows of fluids with single‐integral memory functionals are considered. Evaluation of the stress at a material point involves the deformation history of that point, and a dominant computational cost in finite element approximation is the construction of streamlines. It is shown that the simple crossed‐triangle macro‐element is in many ways an ideal finite element for the difficult non‐linear, non‐self‐adjoint problem. The question as to whether this element produces convergent velocity and pressure solutions is addressed in the light of its failure to satisfy the discrete LBB condition. The effect of the element's ill‐disposed (‘spurious’) pressure modes is discussed, and a pressure smoothing scheme is given which gives good results in Newtonian and non‐Newtonian flows at various Reynolds and Deborah numbers. As an example of the element's success in modelling such flows, the problem of pressure differences in flows over transverse slots is studied numerically. The results are compared with experimental observations of such flows. The effect of fluid memory on the relation between first normal‐stress differences and pressure differ

ISSN:0271-2091    

DOI:10.1002/fld.1650050105

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA residual method of finite differencing the governing differential equation for the elliptic transport problem is presented. The new finite differencing technique is applied to (1) the one‐dimensional transport problem and (2) the cavity flow problem for numerical illustrations. The results indicate the validity of the residual method of finite differencing. The usual method of term‐by‐term finite differencing, and considerations such as central differencing, hybrid differencing and upwind differencing are not needed in the present residual m

ISSN:0271-2091    

DOI:10.1002/fld.1650050106

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe applicability of a finite element‐differential method to the computation of steady two‐dimensional low‐speed, transonic and supersonic turbulent boundary‐layer flows is investigated. The turbulence model chosen for the Reynolds shear stress and turbulent heat flux is theK‐ϵ two‐equation model. Calculations are extended up to the wall and the exact values of the dependent variables at the wall are used as boundary conditions. A number of transformations are carried out and the assumed solutions at a longitudinal station are represented by complete cubic spline functions. In essence, the method converts the governing partial differential equations into a system of ordinary differential equations by a weighted residuals method and invokes an ordinary differential equation solver for the numerical integration of the reduced initial‐value problem. The results of the computations reveal that the method is highly accurate and efficient. Furthermore, the accuracy and applicability of thek‐ϵ turbulence model are examined by comparing results of the computations with experimental data. The agree

ISSN:0271-2091    

DOI:10.1002/fld.1650050107

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050108

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050109

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050101

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY