Engineering topics

Chaussee, D. S.

Publications and source records attributed to Chaussee, D. S..

41 records · Page 3

NASA NTRS1978

Perturbation solutions for transonic flow on the blade-to-blade surface of compressor blade rows

A preliminary investigation was conducted to establish the theoretical basis of perturbation techniques with the objective of minimizing computational requirements associated with parametric studies of transonic flows in turbomachines. The theoretical analysis involved the development of perturbation methods for determining first order changes in the flow solution due to variations of one or more geometrical or flow parameters. The formulation is primarily directed toward transonic flows on the blade to blade surface of a single blade row compressor. Two different perturbation approaches were identified and studied. Applications and results of these methods for various perturbations are presented for selected two dimensional transonic cascade flows to illustrate the advantages and disadvantages of each technique. Additionally, it was found that, for flows with shock waves, proper account of shock displacement was crucial.

Stahara, S. S.↗

NASA NTRS1977

Computational techniques for solar wind flows past terrestrial planets: Theory and computer programs

The interaction of the solar wind with terrestrial planets can be predicted using a computer program based on a single fluid, steady, dissipationless, magnetohydrodynamic model to calculate the axisymmetric, supersonic, super-Alfvenic solar wind flow past both magnetic and nonmagnetic planets. The actual calculations are implemented by an assemblage of computer codes organized into one program. These include finite difference codes which determine the gas-dynamic solution, together with a variety of special purpose output codes for determining and automatically plotting both flow field and magnetic field results. Comparisons are made with previous results, and results are presented for a number of solar wind flows. The computational programs developed are documented and are presented in a general user's manual which is included.

Stahara, S. S.↗

NASA NTRS1977

Application of an axisymmetric implicit blunt body procedure - Computation of solar wind flows past terrestrial planets

A recently developed axisymmetric implicit unsteady Euler equation solver has been applied to the calculation of solar wind flows past terrestrial planets. The primary emphasis of this paper is on the application of that computational technique to the calculation of the flow field properties of steady, axisymmetric, supersonic/hypersonic flows past blunt-nosed shapes characteristic of interplanetary solar wind flows past both magnetic and nonmagnetic planets. The purpose is to demonstrate both the accuracy and flexibility of this new technique as well as to present a novel application of such supersonic blunt-body procedures.

Chaussee, D. S.↗

NASA NTRS1977

Perturbation solutions for blade-to-blade surfaces of a transonic compressor

The paper describes a perturbation method for turbomachinery calculations, particularly where it is necessary to carry out a number of calculations for closely-related flows such as are needed in a parametric study. The method is applied for solving a model problem involving blade-to-blade surfaces of a transonic compressor. Basically, the method makes use of a previously calculated base solution to determine first-order changes in the flow field due to variations in one or more of a variety of geometrical or flow field parameters. The fundamental assumption associated with the perturbation solution is that the magnitude of the deviations from the base solution lies within the range of a linear perturbation analysis. Comparisons are made for results obtained, by varying the thickness ratio of an unstaggered nonlifting cascade composed of biconvex profiles in a flow with an oncoming freestream Mach number of 0.60.

Stahara, S. S.↗

NASA NTRS1975

Inviscid supersonic/hypersonic body flowfields and aerodynamics from shock-capturing technique calculations

A shock-capturing, finite-difference computational procedure has been used to predict the body flowfields over a wide range of initial conditions, and these results have been compared with wind tunnel data. Two different studies have been performed. In the first, details of the shock layer surrounding space shuttle orbiter configurations have been calculated. In the second, the aerodynamic forces and moments on a parametrically varied set of blunt biconic bodies of revolution have been evaluated for angles of attack up to 20 degrees and Mach numbers from 5 to 20.

Chaussee, D. S.↗