Measurements of anisotropic elastic constants of type 308 stainless-steel electroslag welds

In austenitic-stainless-steel weld metal, mechanical anisotropy is caused by preferred local orientation of elongated subgrains and preferred crystallographic orientation. Ultrasonic and static tensile-test methods used to determine elastic stiffness and compliance matrices, respectively, demonstrated that orthotropic symmetry exists. Inversion of this compliance matrix gave a stiffness matrix which showed general agreement between the two methods. It is suggested that the data can be used directly in finite-element analyses of weldments containing Type 308 stainless steel.     

Peripheral variation of heat transfer under pool boiling on tubes

Boiling heat transfer measurements on a tube designed to yield the peripheral variation of heat transfer coefficient without interfering with the nucleation site density are presented. A variation of up to 25% around the tube is found with a maximum at the base. High speed cine photography was used to estimate the variation of mean bubble layer thickness and mean velocities with angle. An iterative heat balance around the periphery indicated a voidage decrease from about unity at the base to 0.3–0.6 at 90°     

Small oscillations of a liquid in a partitioned cylindrical vessel

The equations of motion of a rigid body whose cavity is partially filled with an ideal fluid have been obtained in works of Moiseev [1, 2, 3], Okhotsimskii [4], Narimanov [5], and Rabinovich [6]. All the equation coefficients have been calculated for a cavity in the form of a circular cylinder or two concentric cylinders.The problem of fluid motion in a partitioned cylindrical cavity was considered by Rabinovich [7]. It was also considered by Bauer [8], who analyzed the particular case of vessel motion in the plane of one of the partitions.In the following we consider the two-dimensional motion of a cylinder with radial and annular baffles, and a definition is given of the velocity potential in the case of arbitrary positioning of the radial baffles with respect to the motion plane. Formulas are obtained for determining the parameters of a mechanical analog of the wave oscillations, which consists of two mathematical pendulum subsystems.     

On Saint-Venant's principle in the two-dimensional linear theory of elasticity

Archive for Rational Mechanics and Analysis -     

Energy release rates in a constrained epoxy disc with Hookean and Mooney–Rivlin materials

Assuming that the disc material can be modeled either as Mooney–Rivlin or as Hookean and the steel ring enclosing the disc as Hookean, the energy release rates as a function of the crack length are evaluated and compared. Two loadings are considered––one in which the surface of the star shape hole in the disc is loaded by a uniform pressure and the other in which the temperature of the composite body is uniformly raised. It is found that the linear and the nonlinear analyses give qualitatively similar results for the two loadings. For each load, the energy release rate increases with an increase in the starter crack length, reaches a maximum value and then decreases gradually.     

Computational study of shock wave focusing in a log-spiral duct

The mechanism of shock wave focusing in a two-dimensional log-spiral duct has been investigated here numerically using a finite volume method. This approach is based on a MUSCL TVD scheme with flux-vector splitting applied to the Euler equations. The isopycnics determined from the calculations are compared with the experimental results obtained by use of holographic interferometric photography and are found to be in excellent qualitative agreement with the experiments. The computational results clarify the details of the wave interactions very near to the focus. In particular, phenomena such as the formation of secondary shock waves prior to the implosion, their interaction with the reflected shock and the formation of vortices after the implosion have been examined.     

General series solution for free convection past a non-isothermal vertical flat plate

Summary Free convection past a vertical plate is studied theoretically for a general class of nonlinear wall temperature distributions. Due to the broad approach it is possible in some cases to find two series solutions applying to the same wall temperature distribution which are valid in different parts of the x region. Through graphical joining of both solutions an overall valid solution is obtained. This is illustrated by examples.     

Supersonic three-dimensional flow around a delta wing with blunted leading edges

We consider the problem of steady flow of an inviscid, non-heat-conducting gas about a delta wing which is spherically blunted at the nose and cylindrlcally blunded on the leading edges, at an angle of attack.Several experimental and theoretical studies have been devoted to the investigation of this problem, of which we note [1–4], In the following the three-dimensional method of characteristics using the scheme proposed in [5] is used to calculate the flow fields about such bodies for freestream Mach numbers M=6, 7, 8, and , sweep angle =70°, and angles of attack from 0 to 15°.     

Zusammenhang zwischen induzierter Orientierungsdoppelbrechung und Struktur viskoser Flüssigkeiten und Schmelzen

Zusammenfassung Die vonRaman undKrishnan entwickelte Theorie über die Strömungsdoppelbrechung in Flüssigkeiten wird auf den allgemeinen Fall eines beliebigen Winkels der Polarisationsebene der einfallenden Lichtwelle zur Strömungsrichtung erweitert. Als Ergebnis erhält man eine sin 2-Abhängigkeit, die an Rizinusöl und zwei Glasschmelzen experimentell gut bestätigt wird. Eine Weiterführung der Theorie ergibt, daß allein aus der gemessenen Doppelbrechung der Formtyp der die Flüssigkeit oder Schmelze aufbauenden Teilchen (Ketten-, Flächen- oder Raumstruktur) bestimmt werden kann, wobei noch eine Abschätzung der Anisotropie möglich ist. Eine Überprüfung der erhaltenen theoretischen Ergebnisse an in der Literatur vorliegenden Strömungsdoppelbrechungsmessungen an Flüssigkeiten mit sehr unterschiedlichen Molekülen zeigt gute Übereinstimmung. Weiterhin wird eine größenordnungsmäßige Abschätzung der zwischen den rotierenden konzentrischen Zylindern auftretenden Spannungsdoppelbrechung in hochviskosen Flüssigkeiten und Schmelzen gegeben.Im letzten Abschnitt der vorliegenden Arbeit werden der Aufbau einer Apparatur zur Messung der Orientierungsdoppelbrechung in strömenden Glasschmelzen bis zu Temperaturen von 1000 °C kurz erläutert und Messungen über die Orientierungsdoppelbrechung einer B₂O₃-Schmelze und einer Natriumboratschmelze mit 5,52 Mol% Na₂O mitgeteilt, die nach der dargelegten theoretischen Behandlung ausgewertet wurden. Für die Struktur dieser Schmelzen folgt hieraus: Die B₂O₃-Schmelze besteht auf Grund der Relaxationszeit und der Orientierungsdoppelbrechung aus räumlichen Konglomeraten (Netzwerkbruchstücken) mit einer Kantenlänge von etwa 20 bis 40 Å, die relativ leicht zu trennen und zu orientieren sind. Die Einführung von Na₂O in B₂O₃ bewirkt eine zusätzliche Bildung von 'Trennstellen im Netzwerk (Verkleinerung der Netzwerk-bruchstücke) bei gleichzeitiger Abnahme der Anisotropie der Netzwerkbruchstücke.Vorgetragen auf der Jahrestagung der Deutschen Rheologen-Vereinigung und der Deutschen Rheologischen Gesellschaft in Nad Nauheim am 8. April 1965.     

An implicit mixed enthalpy–temperature method for phase-change problems

A finite element procedure for phase-change problems is presented. Enthalpy and temperature are interpolated separately and subsequently linked via the appropriate relation in the nodes of the mesh during the solution phase. A novel technique is here used where, depending on the characteristics of the problem, either temperature or enthalpy may be considered as primary variable. The resulting algorithm is both efficient and robust and is further easy to implement and generalize to arbitrary finite elements. The capabilities of the method are illustrated by the solution both isothermal and non-isothermal phase-change problems.