Engineering topics

Hamilton, H. H., II

Publications and source records attributed to Hamilton, H. H., II.

25 records · Page 2

NASA NTRS1982

A comparison of computed Space Shuttle Orbiter surface pressures with flight measurements

Vehicles such as the Shuttle Orbiter operate over a wide range of angle of attack when entering the earth's atmosphere. This angle-of-attack range can be divided into two classes, a moderate regime, and a high regime for angles of attack greater than 30 deg. The HALIS (High Alpha Inviscid Solution) code was developed for computing flowfields in the high angle-of-attack regime. The present investigation is concerned with conducting a comparison of HALIS results with wind-tunnel data and the limited flight data from STS-1. The investigation shows that at high angle-of-attack, the axial flow over the entire windward surface can be subsonic, and, for those conditions, where the subsonic axial flow is confined to the nose of the vehicle, embedded regions of subsonic axial flow may be found along the vehicle strake tips.

Weilmuenster, K. J.↗

NASA NTRS1981

A method for computation of inviscid three-dimensional flow over blunt bodies having large embedded subsonic regions

A computational technique for computing the three-dimensional inviscid flow over blunt bodies having large regions of embedded subsonic flow is detailed. Results, which were obtained using the CDC Cyber 203 vector processing computer, are presented for several analytic shapes with some comparison to experimental data. Finally, windward surface pressure computations over the first third of the Space Shuttle vehicle are compared with experimental data for angles of attack between 25 and 45 degrees.

Weilmuenster, K. J.↗

NASA NTRS1980

Calculation of laminar heating rates on three-dimensional configurations using the axisymmetric analogue

A theoretical method was developed for computing approximate laminar heating rates on three dimensional configurations at angle of attack. The method is based on the axisymmetric analogue which is used to reduce the three dimensional boundary layer equations along surface streamlines to an equivalent axisymmetric form by using the metric coefficient which describes streamline divergence (or convergence). The method was coupled with a three dimensional inviscid flow field program for computing surface streamline paths, metric coefficients, and boundary layer edge conditions.

Hamilton, H. H., II↗

NASA NTRS1980

Viscous compressible flow about blunt bodies using a numerically generated orthogonal coordinate system

A numerical solution to the Navier-Stokes equations was obtained for blunt axisymmetric entry bodies of arbitrary shape in supersonic flow. These equations are solved on a finite difference mesh obtained from a simple numerical technique which generates orthogonal coordinates between arbitrary boundaries. The governing equations are solved in time dependent form using Stetter's improved stability three step predictor corrector method. For the present application, the metric coefficients were obtained numerically using fourth order accurate, finite difference relations and proved to be totally reliable for the highly stretched mesh used to resolve the thin viscous boundary layer. Solutions are obtained for a range of blunt body nose shapes including concavities.

Graves, R. A., Jr.↗

NASA NTRS1980

Application of a numerically generated orthogonal coordinate system to the solution of inviscid axisymmetric supersonic flow over blunt bodies

A numerically generated orthogonal coordinate system (with the body surface and shock wave as opposite boundaries) was applied with a time asymptotic method to obtain steady flow solutions for axisymmetric inviscid flow over several blunt bodies including spheres, paraboloids, ellipsoids, hyperboloids, hemisphere cylinders, spherically blunted cones, and a body with a concavity in the stagnation region. Comparisons with experimental data and with the results of other computational methods are discussed. The numerically generated orthogonal coordinate system is described and applications of the method to complex body shapes, particularly those with concave regions, are discussed.

Hamilton, H. H., II↗

NASA NTRS1979

A hybridized method for computing high-Reynolds-number hypersonic flow about blunt bodies

A hybridized method for computing the flow about blunt bodies is presented. In this method the flow field is split into its viscid and inviscid parts. The forebody flow field about a parabolic body is computed. For the viscous solution, the Navier-Stokes equations are solved on orthogonal parabolic coordinates using explicit finite differencing. The inviscid flow is determined by using a Moretti type scheme in which the Euler equations are solved, using explicit finite differences, on a nonorthogonal coordinate system which uses the bow shock as an outer boundary. The two solutions are coupled along a common data line and are marched together in time until a converged solution is obtained. Computed results, when compared with experimental and analytical results, indicate the method works well over a wide range of Reynolds numbers and Mach numbers.

Weilmuenster, K. J.↗

NASA NTRS1978

Solution of axisymmetric and two-dimensional inviscid flow over blunt bodies by the method of lines

Comparisons with experimental data and the results of other computational methods demonstrated that very accurate solutions can be obtained by using relatively few lines with the method of lines approach. This method is semidiscrete and has relatively low core storage requirements as compared with fully discrete methods since very little data were stored across the shock layer. This feature is very attractive for three dimensional problems because it enables computer storage requirements to be reduced by approximately an order of magnitude. In the present study it was found that nine lines was a practical upper limit for two dimensional and axisymmetric problems. This condition limits application of the method to smooth body geometries where relatively few lines would be adequate to describe changes in the flow variables around the body. Extension of the method to three dimensions was conceptually straightforward; however, three dimensional applications would also be limited to smooth body geometries although not necessarily to total of nine lines.

Hamilton, H. H., II↗