摘要:

Plane parallel flow between rigid plates of an incompressible inviscid fluid is considered. Anecessary and sufficientcondition for infinitesimal stability is derived in the special case wherew″ has only a single zero andw′ > 0 wherew(x) is the velocity profile between the plates. A generalsufficientcondition for instability is also obtained.

ISSN:0031-9171    

DOI:10.1063/1.1711237

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

A short derivation of Wild's inversion of the Boltzmann equation is given. It is shown that if Wild's formula is to be used for an iterative solution, the Bhatnagar‐Gross‐Krook equation is recovered as the first step in a particular case, in which the ``initial guess' is supported by classical mean‐free‐path concepts. Use of different initial guesses is considered, particularly those based on the Mott‐Smith model. Connections between the iterative method and the classical expansion procedures are indicated.

ISSN:0031-9171    

DOI:10.1063/1.1711238

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Turbulent energy components in a uniform shear flow with weak, homogeneous turbulence are reported. These results complement Deissler's calculations for the case of initially isotropic turbulence and provide a complete description of the effects of the mean‐velocity gradient.

ISSN:0031-9171    

DOI:10.1063/1.1711239

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The case of one‐dimensional magnetogasdynamic flow with heat transfer is analyzed. It is shown that the flow variables can be expressed as functions of the dimensionlessKnumber. The important flow regimes are delineated and it is observed that although the flow is reminiscent of classical flow with heat transfer, there do appear significant differences.

ISSN:0031-9171    

DOI:10.1063/1.1711240

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

An experimental study was made of thermal transport at the stagnation point of a 1‐in.‐diam hemisphere‐cylinder model immersed in a high enthalpy flow of shock‐heated argon. Emphasis was placed on the separation of convective and radiative transport. Variation of operating parameters gave regimes in which (1) the heat transfer was almost wholly of the aerodynamic or convective type, or (2) both convective and radiative heat transfer had to be considered. Separate measurements of the total heat transfer and of the radiative component permitted separation of the former into convective and radiative parts. A limited comparison is made between the convective results and those obtained earlier for unionized argon. The radiative transport is compared with that obtained theoretically from the Kramers bremsstrahlung theory as applied to an argon plasma.

ISSN:0031-9171    

DOI:10.1063/1.1711241

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The microwave attenuation of air in Mach range 8–12 is investigated at initial pressures of 5 mm Hg. It is shown (a) that the experimental peak attenuation is larger than given by conventional theory; (b) that the time dependence of the attenuation curve gives important information regarding the build‐up of the ionization as a function of time, the contact surface and the zone behind it.It is found that the microwave attenuation rises approximately linearly as a function of time to its peak value. The testing time is shorter than that predicted from ideal shock theory but sufficient to establish equilibrium. The electron density changes abruptly upon arrival of the driver gas. However, an appreciable electron density exists over a large region behind the contact surface indicating strong interface mixing. It is also shown that the nature of the surface of the shock tube influences the peak attenuation and the time dependence of this attenuation.

ISSN:0031-9171    

DOI:10.1063/1.1711242

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

A study has been conducted of the phenomena occurring when a hydrogen plasma is caused to flow through a transverse magnetic field. Plasma polarization effects were studied as well as the deceleration processes which occurred when large currents were extracted from the plasma. Standing ``wedge‐shaped'' shock waves were observed when sufficient current was extracted to permit the deceleration phenomena to be manifested. The effective plasma resistance between electrodes was determined, and a correlation made with plasma conductivity measurements, including boundary layer effects. Finally, a determination was made of the power and energy extracted from the plasma.

ISSN:0031-9171    

DOI:10.1063/1.1711243

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

Experimental results of applying the method of two‐wavelength, streak interferometry are given for the cylindrical, time‐dependent flow of ionized argon produced by an exploding wire. Measurements from simultaneous streak interferograms at wavelengths 5460 and 4358 Å are used to determine contour charts of electron concentration and mass density of the shock‐arc‐heated argon plasma. Where thermal equilibrium can be assumed, values of velocity, pressure, and temperature can be deduced. The resulting temperatures agree well with those obtained from the Saha relation at the measured degree of ionization. The reduction equations and assumptions needed for the axisymmetric analysis are given. An estimate is made of the error in measured mass density caused by multiple ionization.

ISSN:0031-9171    

DOI:10.1063/1.1711244

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

An experimental study of the properties of supersonic plasma streams which have been seeded with small amounts of an electronegative gas is described. It has been found that striking reductions of the electron and ion densities of the plasma can be achieved using sulfur hexafluoride (SF6) as the seed gas. The properties of seeded argon streams at pressures of 1 Torr and velocities of about Mach 2 have been studied using double‐probe and microwave (9.2 Gc/sec) scattering techniques. The results show that when the SF6is introduced with a concentration of only 5 × 10−4relative to that of the argon in the stream, the plasma is quenched almost completely. Under these conditions the reflection of microwaves from the stream is reduced by 20 dB and the probe measurements show the presence of the ``hole'' cut in the plasma by the SF6. Measurements of seeding with argon, nitrogen, and oxygen in the argon streams are also discussed.

ISSN:0031-9171    

DOI:10.1063/1.1711245

出版商:AIP    

年代:1964

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.1711247

出版商:AIP    

年代:1964

数据来源: AIP