摘要:

AbstractA method is presented to calculate the low‐speed incompressible separated flow around multi‐element aerofoils. The geometries of multi‐element aerofoils in the physical plane are completely arbitrary and are transformed into multiple circles in the computational plane by a conformal mapping technique. Jacob's model, which distributes sources on the separated surfaces of multi‐element aerofoils to simulate the effects of separation, is adopted here. The position of the separated point and the pressure on the surfaces of multi‐element aerofoils are calculated by iteratively coupling the potential flow and boundary layer. The effects of the boundary layer are simulated by modification of the boundary condition. All iterative procedures converge rapidly as a result of using the fast Fourier transform (FFT)

ISSN:0271-2091    

DOI:10.1002/fld.1650180502

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper presents a numerical method for fluid flow in complex three‐dimensional geometries using a body‐fitted co‐ordinate system. A new second‐order‐accurate scheme for the cross‐derivative terms is proposed to describe the non‐orthogonal components, allowing parts of these terms to be treated implicitly without increasing the number of computational molecules. The physical tangential velocity components resulting from the velocity expansion in the unit tangent vector basis are used as dependent variables in the momentum equations. A coupled equation solver is used in place of the complicated pressure correction equation associated with grid non‐orthogonality. The co‐ordinate‐invariant conservation equations and the physical geometric quantities of control cells are used directly to formulate the numerical scheme, without reference to the co‐ordinate derivatives of transformation. Several two‐ and three‐dimensional laminar flows are computed and compared with other numerical, experimental and analytical results to validate the solution method. Good agreement

ISSN:0271-2091    

DOI:10.1002/fld.1650180503

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper deals with the non‐stationary incompressible Navier‐‐Stokes equations for two‐dimensional flows expressed in terms of the velocity and pressure and of the vorticity and streamfunction. The equivalence of the two formulations is demonstrated, both formally and rigorously, by virtue of a condition of compatibility between the boundary and initial values of the normal component of velocity. This condition is shown to be the only compatibility condition necessary to allow for solutions of a minimal regularity, namelyH1for the velocity, as in most current numerical schemes relying on spatial discretizations of loc

ISSN:0271-2091    

DOI:10.1002/fld.1650180504

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA study is reported on the possibility of improving the speed of convergence of existing numerical programmes for the simulation of flow in combustion chambers by applying the multigrid method to the pressure correction phase only. A version of the multigrid algorithm is introduced for this purpose which achieves a 1:10 residual reduction in a singleV(1, 1) cycle. The overall decrease in computation time with respect to an industry‐standard SIMPLE algorithm with single‐grid pressure correction ranges from four to five times for SIMPLE itself and several other well‐known algorithms to six times for a newly developed pressure correction strategy we call difference operator triangularization

ISSN:0271-2091    

DOI:10.1002/fld.1650180505

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractTranspiration is a technique in which extra non‐physical normal flows are created on an aerofoil surface in order to form a new streamline pattern such that the surface streamlines no longer follow the aerofoil surface under inviscid flow. The transpiration model is an important technique adopted in aerofoil design either to avoid mesh regeneration when aerofoil profile co‐ordinates are adjusted or to find shape corrections in inverse design methods. A first‐order approximation (with respect to the normal streamline displacement) to the transpiration model is commonly adopted; it is shown that this can be a poor approximation especially in regions of high curvature. In this paper more accurate approximations are developed to address this problem and improve the acc

ISSN:0271-2091    

DOI:10.1002/fld.1650180506

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractSelf‐similar solutions to the Riemann problem for water with the modified Tait equation of state are presented. The methods of Smoller for gas dynamics are employed to reduce the problem to the solution of a single non‐linear equation. The same methods are used for solving the Riemann problem at a gas‐water interface. In both cases the method of interval bisections affords a solution technique free of problems with conver

ISSN:0271-2091    

DOI:10.1002/fld.1650180507

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650180508

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650180501

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY