摘要:

Thermodynamic properties and molecular pair distribution functions are calculated for the one‐dimensional spherical model of a gas with an attractive interaction outside of a hard core, in the limit as the range of attractive forces becomes infinite. In this limit, a phase transition appears, and the equation of state consists of analytically different parts. The calculations are made using the canonical ensemble which permits a description of the two‐phase region. Properties in this region are found to have a simple description in terms of the coexistence of gas and liquid phases.

ISSN:0031-9171    

DOI:10.1063/1.1706787

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The partition function of a system ofNidentical rigid rods connected by identical springs is reduced to a onefold integration. This integration is explicitly performed in the limitN→ ∞ by the method of steepest descent. The system behaves respectively as a gas and as a solid in two different limiting cases. The calculated isotherms and specific heat show that the transition between these limiting cases is continuous.

ISSN:0031-9171    

DOI:10.1063/1.1706788

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Measurements of the thermal conductivity &lgr; of O2and O2‐H2O mixtures by the line source technique over the temperature range 300–1100 °K are presented. In the case of pure O2, excellent agreement of the data with previously reported results obtained elsewhere with an entirely different method establishes the thermal conductivity of this gas rather well. The composition dependence of &lgr; for O2‐H2O mixtures at various temperatures is compared with theoretical predictions. The simple application of the Hirschfelder mixture relation, using all experimental input data and ignoring the polarity of H2O, gives excellent agreement with experiment. A rough attempt to include the effect of resonant interchange of rotational energy (recently treated by Mason and Monchick) leads to poorer agreement.

ISSN:0031-9171    

DOI:10.1063/1.1706789

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

General equations are derived for the dynamics of a fluid under initial stress in an arbitrary potential field and perturbed from equilibrium. The motion is described in terms of the displacements of the fluid particles from their equilibrium position. A class of equations is obtained which is applicable to large displacements. Complete linearization leads to two types of equations. One type called ``un‐modified'' corresponds to the viewpoint of the theory of elasticity. The ``modified'' equations representing the other type are expressed in terms of buoyancy forces. The modified equations lead to a conceptually useful analog model for internal gravity waves in a liquid. For a constant gravity field the linear equations are also applicable to large displacements. Classical examples for a constant gravity field are discussed as illustrations.

ISSN:0031-9171    

DOI:10.1063/1.1706790

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The steady flow of a certain non‐Newtonian fluid in an annulus between two coaxial cylinders rotating with uniform angular velocities about the common axis is studied when there is suction at one wall and injection at the other. The stress matrixTfor the non‐Newtonian fluid is given byT= ‐pI+ &agr;1A1+ &agr;2A2, wherepis the pressure,Iis the unit matrix, &agr;1, &agr;2are constants andA1,A2are kinematic matrices. It is found that in the case of no suction and injection, the velocity field is not affected by the presence of the non‐Newtonian term &agr;2A2, though the pressure field is affected. On the other hand, if there is suction and injection, however small, the non‐Newtonian term affects the velocity field and the nature of this effects is investigated for sufficiently small suction and injection velocities.

ISSN:0031-9171    

DOI:10.1063/1.1706791

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The behavior of a weak fluctuating magnetic field in a turbulent electrically conducting fluid with large magnetic Prandtl number is re‐examined, without using vorticity analogy. For large magnetic Prandtl number, the characteristic length of the small eddies of turbulence is much larger than that of the small loops of the magnetic field. By inferring that the small eddies of turbulence are mainly responsible for the change of the fluctuation intensity of the magnetic field and by utilizing Batchelor's mixing approach, visualizing the turbulent velocity field as effectively a rather persistent uniform straining motion for the small‐scale variation of magnetic field, it was found that the fluctuation intensity of the magnetic field grows due to turbulent motion for very large magnetic Prandtl number [(&ngr;/&lgr;) > 100, say] and approaches a constant value asymptotically. The rate of growth is found to be a function of &ngr;/&lgr; and &tgr; (the product of time and the turbulent straining rate).

ISSN:0031-9171    

DOI:10.1063/1.1706792

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

It is found that certain parallel magnetic fields can destabilize the plane Couette flow of a perfectly conducting fluid, though this flow is known to be stable when there is no field. The destabilizing role of the rigidity of the field is attributed to its ability to prevent the stretching of curves of constant perturbation vorticity by the shear. Unstable long waves transfer energy to the mean magnetic field from the kinetic field by means of the Reynolds stresses. This suggests the possibility of maintaining an electrical current which is initially introduced between two differentially rotating cylinders.

ISSN:0031-9171    

DOI:10.1063/1.1706793

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Laminar and turbulent two‐dimensional incompressible viscous free jet flow is studied for a conducting fluid. A constant magnetic field transverse to the axis of the jet is considered and the stream functions are expanded about the nonmagnetic jet solutions. The parameter of expansion is the square of the Hartmann number divided by the Reynolds number and results are computed to the first order in the expansion parameter. The results indicate a qualitative similarity for both the laminar and turbulent cases. The magnetic field depresses the axial velocity of the jet near the center of the jet but increases the axial velocity in the outer regions of the jet. The transverse velocity at the jet boundary is reduced in the presence of the magnetic field. The discharge rate of the jet is also reduced in the presence of magnetic field.

ISSN:0031-9171    

DOI:10.1063/1.1706794

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Generalizing a particular case studied by Jones, Stanyukovich, and Manson have given general equations connecting (1) the Chapman‐Jouguet detonation pressure; (2) the derivative &agr; =p(∂v/∂E)pof the equation of stateE(p, v) of the product gases; (3) the derivatives of the detonation velocityDwith respect to the thermodynamic variables defining the initial state of the explosive, such as the initial density &rgr;0; (4) the variablesDand &rgr;0themselves.After presenting a careful derivation of this result, it is pointed out that in conjunction with experimental observations of (a) the unsupported detonation‐wave pressurepand velocityDand (b) the derivatives ofDwith respect to two independent initial variables (e.g., &rgr;0andE0), it permits an experimental test of the basic assumptions of detonation theory, namely the assumption of laminar flow and the Chapman‐Jouguet hypothesis. Several experimental possibilities are suggested for condensed explosives, where direct experimental observations (such as White's interferometric detection of apparent turbulent flow in gaseous detonations) are difficult. An erroneous criticism, by Pujol and Manson, of Jones' relation as applied to the density dependence of the detonation velocity in low‐density solid explosives is also corrected.

ISSN:0031-9171    

DOI:10.1063/1.1706795

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

As the curvature of shock waves increases, the shock structure becomes two dimensional, and the usual Hugoniot jump conditions no longer hold. An equation has been derived for the structure of such a two‐dimensional non‐Hugoniot shock in the case of weak shocks with Mach numbers close to one. The development of this equation from the Navier‐Stokes equations is based on the assumptions that the vertical velocity is of order (M1* − 1)3/2and that the flow within the shock is irrotational. From the derivation it appears that the non‐Hugoniot region behaves as an acoustic wave driven by higher‐order viscous effects. The properties of the above equation, which has been called the viscous‐transonic or V‐T equation have been investigated. The V‐T equation appears to be a combination of Burgers' equation for weak normal shock structure and the transonic equation. It is shown that the structure of oblique shocks is a similarity solution of the V‐T equation. Proper formulation of boundary conditions is considered and a uniqueness proof is given for a particular restricted boundary value problem.

ISSN:0031-9171    

DOI:10.1063/1.1706796

出版商:AIP    

年代:1963

数据来源: AIP