摘要:

Measurements of the rotational temperature of electron‐beam excited nitrogen have been made along the axis of a free jet under various flow conditions. Temperatures calculated from the isentropic flow equations are compared with those derived from the rotational spectra. Discrepancies between the two temperature determinations led to an investigation of the rotational spectrum of nitrogen in thermodynamic equilibrium at 300 and at 78°K. Results of the ``static'' gas measurements are presented which indicate that existing models of the electron‐beam excitation—de‐excitation process may be incorrect.

ISSN:0031-9171    

DOI:10.1063/1.1762070

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A modified Chapman—Enskog technique developed for a partially ionized gas in an electric field is generalized to include the effects of a magnetic field. The method allows the electron and heavy particle temperatures to differ while requiring all species to have the same macroscopic velocity to zero order. Expressions are obtained for the transport properties of such a gas and a complete set of self‐contained magnetohydrodynamic equations is given. As an example, the transport properties of a fully ionized gas containing a single ion species are evaluated using the cutoff Coulomb potential. In the limit of equal electron and ion temperatures, the results are in agreement with previous results.

ISSN:0031-9171    

DOI:10.1063/1.1762071

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The classical second virial coefficient and its first two quantum corrections are evaluated for a repulsive exponential potential by the use of Laplace transforms. The results are used to estimate the effect of the intermolecular attraction in the high‐temperature second virial coefficient of4He and in its first quantum correction. An approximation is found for this first quantum correction at temperatures above 100°K for4He. A simplified expression for theS‐wave phase shift of the exponential repulsion is derived and is used to calculate a quantum‐mechanical turning point for wave packets or effective hard core radius. Similar methods are applied to the Morse potential to evaluate the classical second virial coefficient and its first quantum correction and theS‐wave phase shift.

ISSN:0031-9171    

DOI:10.1063/1.1762072

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The stability of laminar boundary layers at separation is considered. The velocity distribution is represented by (1) a Pohlhausen fourth‐degree polynomial P4, and (2) by a Falkner—Skan similarity profile at separation, Hartree &bgr; = − 0. 1988. The Orr—Sommerfeld equation is integrated using Runge—Kutta with Gram—Schmidt orthonormalization. Using single precision arithmetic, the method leads to satisfactory answers at Reynolds numbersR1= 100 000 and larger. In either case the minimum critical Reynolds number is found to be of the order of 100. It is found that the neutral curves for the P4 profile obtained by solving the Orr—Sommerfeld equation, whether exactly (numerically) or within the framework of the asymptotic approximations, approach along the upper branch the same asymptotic value, namely &agr;1= 0.8028 (in the case of the &bgr; = − 0. 1988 profile, however, the corresponding values is &agr;1= 1.240). It is also found that the asymptotes to the lower branch in both cases vary with &agr;1according toR11/3∼&agr;1−7/9(in the case of the &bgr; = − 0. 1988 profile however, the corresponding variation isR11/3∼ &agr;1‐ 0. 477).

ISSN:0031-9171    

DOI:10.1063/1.1762073

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The flow of micropolar fluids between two concentric cylinders, is analyzed first for the use of Couette flow with ∂p/∂&thgr;, then for the case of Poiseuille flow. The results are presented graphically and compared with the classical ones, and the differences are discussed.

ISSN:0031-9171    

DOI:10.1063/1.1762074

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The governing equations are given for a fluid with deforming microstructure by postulating an energy balance, an entropy production inequality, and a principle of material frame indifference. A canonical form of the energy equation is derived which serves as a guide to define a simple deformable directed fluid. A theory for such fluids is developed.

ISSN:0031-9171    

DOI:10.1063/1.1762075

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Exact magnetohydrodynamic solutions for incompressible fluids, valid for all values of conductivity and viscosity, are found. These collinear magnetohydrodynamic fields have magnetic surfaces corresponding to stream surfaces.

ISSN:0031-9171    

DOI:10.1063/1.1762076

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Ring vortices are induced after the passage of an axial current through a stagnant conducting liquid contained between two concentric, corrugated glass tubes with a strong current flowing along the common axis of the tubes. Experiments have been conducted using transparent aqueous solution of copper sulfate suspended with fine aluminum powder for flow visualization. Flow patterns are photographed for the cases that the sinusoidal deformations on the tube walls are either in phase or completely out of phase, and one of the tubes is straight. The result agrees considerably well with that obtained previously from a linearized theory.

ISSN:0031-9171    

DOI:10.1063/1.1762077

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The measurement of ionization rates, electron density, and ionization time in thermally ionized gases, by means of a microwave technique, is discussed. The technique used in this work utilizes a so‐called ``end‐wall'' microwave resonant cavity. It is essentially a microwave cavity operated in the TE011mode with a plasma forming one end wall. Since the resonant frequency of such a cavity is a function of the axial length of the cavity, a variable density plasma with its corresponding variable conductivity is utilized to tune the cavity to different resonant frequencies. It is shown that by applying two frequencies to the cavity separated from each other by a known &Dgr;f, which is small compared to the resonant frequency of the closed cavity, a simple method is arrived at to measure electron density, ionization rate, and ionization time.

ISSN:0031-9171    

DOI:10.1063/1.1762078

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A plasma wind tunnel has been constructed and the super‐Alfve´nic flow over a magnetic obstacle studied. The wind tunnel produces a steady (10−3sec) flow of high enthalpy (∼100 eV), high density (1014) plasma. The flow of this high conductivity plasma has been studied using magnetic field probes. The interface and shock wave produced in front of a magnetic obstacle in the flow have been studied. The shock wave is shown to satisfy the usual magnetohydrodynamic Rankine—Hugoniot relations.

ISSN:0031-9171    

DOI:10.1063/1.1762079

出版商:AIP    

年代:1967

数据来源: AIP