Axisymmetric Duct Research Articles

Determination of Internal Gas Flows by a Transient Numerical Technique

A time-dependent numerical method is developed for inviscid mixed subsonic-supersonic flows with shocks. The analysis is based on the Lax-Wendroff procedure but adds special treatments of the boundary conditions, a mapping of the physical contours and a damping term to provide stable solutions for planar and axisymmetric passages of arbitrary shape. Both transient and steady-state flows are computed with special emphasis being placed on the analysis of rapidly accelerating flows in axisymmetric ducts with sharp wall curvature. Results obtained compare favorably with experimental data and with prior analyses in those restricted regions where they have been applicable. In particular, excellent agreement is achieved between the present theory and experiment for the previously unsolved case of mixed flows in nozzles involving rapid subsonic contractions, sharp wall curvature at the throat and shocks in the supersonic flow portion. Here normal comparison parameters such as centerline and wall Mach number distributions, sonic line position and discharge coefficient are matched to a high degree of accuracy.

Laminar boundary layer in axisymmetric swirling ducted gas flow

Several studies have been published [1–3] in which the authors solve the problem of the laminar boundary layer in an incompressible fluid on the walls of an axisymmetric duct in the presence of swirl in the outer flow. In [3], Loitsyanskii's parametric method of [4, 5], generalized to the case of three-dimensional flow, is used to solve this problem.

Accurate Difference Methods for Linear Ordinary Differential Systems Subject to Linear Constraints

We consider the general system of n first order linear ordinary differential equations y'(t)=A(t)y(t)+g(t), a<t< b, subject to "boundary" conditions, or rather linear constraints, of the form Σ^(N)_(ν=1) B_(ν)y(τ_ν)=β Here y(t), g(t) and II are n-vectors and A(t), Bx,..., BN are n × n matrices. The N distinct points {τ_ν} lie in [a,b] and we only require N ≧ 1. Thus as special cases initial value problems, N=1, are included as well as the general 2-point boundary value problem, N=2, with τ_1=a, τ_2=b. (More general linear constraints are also studied, see (5.1) and (5.17).)

Heat Transfer and Laminar Boundary-Layer Distributions in an Internal Subsonic Gas Stream at Temperatures Up to 13,900 Deg R

Radial distributions of velocity, enthalpy, and mass flux have been evaluated experimentally in a laminar boundary layer from calorimetric probe measurements obtained in a subsonic flow of arc-heated argon in the entrance region of an axisymmetric constant-diameter duct. Longitudinal distributions of heat flux were also determined. Because of the large free stream to wall temperature ratios the boundary-layer mass flux exceeded that of the free stream sufficiently to produce negative values of the displacement thickness. The longitudinal distributions of the heat transfer and the radial distributions of the enthalpy difference and the velocity were found to agree reasonably well with laminar boundary-layer predictions which account for large variations in properties.

Erratum: “Incompressible Jet Mixing in Converging-Diverging Axisymmetric Ducts” (Journal of Basic Engineering, 1967, 89, pp. 210–220)

Erratum: “Incompressible Jet Mixing in Converging-Diverging Axisymmetric Ducts” (Journal of Basic Engineering, 1967, 89, pp. 210–220)

Incompressible Jet Mixing in Converging-Diverging Axisymmetric Ducts

A test has been made of the constant turbulent Reynolds number hypothesis for a turbulent jet flow in a converging-diverging axisymmetric tube. Using the free turbulent jet as the sole source of data for evaluation of the Reynolds number, and velocity shear distributions, the general ducted flow was predicted with the aid of appropriate similarity relations. Calculated results are compared with the extensive and consistent data of Helmbold; good agreement is observed. It is found that the methods of calculation employed can be considerably simplified without large effect on the calculated results. The existence and extent of zones of recirculation are also discussed.

On the Tendency to Self-Preservation in Axisymmetric Ducted Jets

If it is assumed that the mean-velocity profiles of a ducted jet are similar in form sufficiently for downstream of the orifice it is possible, as shown in earlier papers [1, 2, 3], to integrate the equations of motion using the boundary-layer approximation and assuming a constant-energy secondary stream. It is necessary to know when and how this limiting profile is reached, and whether a similar tendency to self-preservation of the components of the velocity fluctuations is observed before the jet reaches the duct-wall boundary layer. Measurements have been made in an axisymmetric ducted air jet of the mean and fluctuating velocities, jet width, secondary-stream velocity, ductwall static pressure, and the boundary layer thickness. Results are compared with values predicted by the approximate jet theory. The authors define form factors calculated from measured profiles of mean velocities, of radial and longitudinal components of the velocity fluctuations, and of the shear stress. The variation of these form factors indicates a definite tendency to similarity for the mean velocity profiles; however, departures from similarity persist for the velocity fluctuations to the limit of measurements, about three duct diameters (40 nozzle diameters).

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Closure to “Discussions of ‘On the Tendency to Self-Preservation in Axisymmetric Ducted Jets’” (1964, ASME J. Basic Eng., 86, pp. 771–775)

Closure to “Discussions of ‘On the Tendency to Self-Preservation in Axisymmetric Ducted Jets’” (1964, ASME J. Basic Eng., 86, pp. 771–775)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Discussion: “On the Tendency to Self-Preservation in Axisymmetric Ducted Jets” (Curtet, R., and Ricou, F. P., 1964, ASME J. Basic Eng., 86, pp. 765–771)

Centerline Flow Gradients in Axisymmetric Ducts

Centerline Flow Gradients in Axisymmetric Ducts

A Simple Method of Constructing Duct Models for the Electrolytic Tank

A problem which occurs frequently is that of choosing a suitable shape for a duct, such as a wind tunnel contraction or an air intake. Basically similar problems, involving potential flow fields, occur in other branches of engineering, particularly in electrical engineering, and the electrolytic tank is now established as a tool which may usefully be employed in their investigation. The use of the simple shallow tank is limited to those fields which can be treated as two-dimensional or axisymmetric, but many problems fall within these categories.In forming a duct model for the electrolytic tank the walls of the duct are represented by insulating surfaces, and electrodes are positioned to represent two suitable velocity potential surfaces up- and down-stream of the duct. To represent a sector of an axi-symmetric duct the base of the tank must be inclined at 3°-5° to the horizontal and the water line on the tank base then represents the axis of symmetry.