摘要:

AbstractIt is shown here that the solutions of the governing partial differential equations fail to behave well for three well‐known methods of analysis and design for the computation of inviscid flows in turbomachines and for time‐dependent transonic airflows. The first two examples are related to flows in turbomachines: the so‐called ‘streamline curvature methods’ and the proposition of C. H. Wu to reduce the solution of an essentially three‐dimensional internal flow problem to successive two‐dimensional ones. Finally, time‐dependent compressible and irrotational flows which employ the density and the velocity potential as dependent variables

ISSN:0748-8025    

DOI:10.1002/cnm.1630020103

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630020104

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn evaluation of Sobieczky's fictitious gas technique is presented as applied to the design of a transonic rotor. A representative transonic compressor rotor was redesigned using Sobieczky's technique in an ‘onion peel’ fashion. The design was followed by a full three‐dimensional inviscid analysis of the new rotor, to determine whether spanwise redistribution of the streamlines in the new flow would invalidate the technique by causing shocks to reappear. This analysis verified the suppression of shocks present in the initial flow field. This demonstrates that the technique can be used in practice to improve the design of transonic rotors and stators with subsonic flow at the inlet and

ISSN:0748-8025    

DOI:10.1002/cnm.1630020105

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA finite element formulation and algorithm for calculation of shock‐free compressible flows and design of shockless airfoils is developed. The formulation is conceptually similar to current finite difference methods in that it combines the use of a fictitious gas for a regularized compressible potential flow calculation, together with the method of characteristics in the supersonic pocket. The redesigned shock‐free airfoil surface is determined from a subsidiary streamline calculation. In the present analysis, a variational finite element method is used and optimal control techniques are employed to compute the solution to the discrete problem. Numerical results and comparison studies with finite difference results for a representative case are gi

ISSN:0748-8025    

DOI:10.1002/cnm.1630020106

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA numerical procedure has been developed for the design of shock‐free supercritical airfoil sections with an allowance for viscous effects, provided the boundary layer is fully attached over the airfoil. The method described combines, in an interative process, an inviscid hodograph‐based inverse‐design algorithm (IDA) developed by the author and the inverse‐boundary layer algorithm (LTBLCEQL) by Miner, Anderson and Lewis. Here, the subcritical portion of the inviscid solution is obtained by solving the full stream function equation in a computational plane which is a conformal map of the two‐sheeted hodograph plane. For the supercritical portion, a characteristics calculation is carried out in the hodograph plane. Viscous effects are then incorporated via the displacement surface concept. A Crank–Nicolson type implicit finite difference scheme is utilized to solve the laminar and turbulent boundary layer equation which are expressed in Levy–Lees variables. A transition model allowing for gradual, rather than instantaneous, transition to turbulent flow is also incorporated. The numerical coupling procedure is applied to the design of two airfoil sections for a range of supercritical

ISSN:0748-8025    

DOI:10.1002/cnm.1630020107

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630020108

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe problem of designing three‐dimensional configurations with specified skin friction is addressed. For wall flows that are boundary layers, the following procedure is described. The input skin friction is used as a target for an inverse boundary layer calculation. The resulting pressure distribution is used as input to an inviscid configuration design procedure. This procedure computes the body geometry. The procedure is demonstrated by modifying the lift of a wing section, in compressible flo

ISSN:0748-8025    

DOI:10.1002/cnm.1630020109

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn integral equation method is presented for the quasi three‐dimensional inverse aerofoil and cascade design. Fluid compressibility and vorticity diffusion are introduced by means of sources resp. distribution functions for the boundary vortices. Application of a Taylor development to the kinematical condition, enlarged by an additional source term, leads to a linear equation system for the profile shape and the channel height. Thus, both the velocity distribution and the profile thickness can be prescribed. Several calculations of aerofoil sections and cascades are presented, which illustrate the accuracy and possibilities of the metho

ISSN:0748-8025    

DOI:10.1002/cnm.1630020110

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630020111

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630020112

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY