摘要:

In order to investigate the validity of appending the Gorter‐Mellink friction term to the equations of motion of liquid helium, the temperature was measured along the axis of a channel carrying a supercritical heat current. A single thermomenter on a traversing assembly was used permitting local measurements both in the interior of the channel and in the jet formed in the free fluid. The temperature gradient in the interior of the channel is found to be in agreement with the Gorter‐Mellink law up to the lambda point, but goes to zero within a channel radius, in the free jet. The Gorter‐MellinkA (T )was also measured up to the lambda point. A much stronger divergence is found asT &lgr;is approached than was indicated by previous measurements.

ISSN:0031-9171    

DOI:10.1063/1.1694214

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Solitary waves are generated on the interface between two immiscible liquids with free upper surface; their behavior is generally consistent with that predicted by the Korteweg‐de Vries equation. Inviscid theory expanded to include capillary effects predicts unchanged wave speed and narrowed wave shape to first order in amplitude regardless of upper boundary condition; but measured speeds are down 8% and narrowing is substantially greater at very small amplitudes. The speed difference appears consistent with an interfacial viscous boundary layer. The critical depth ratio separating the elevation and depression modes of the stable gravity solitary wave ageees with prediction in the inviscid limit. The design of a programmed, variable flux wavemaker for efficiently generating interfacial waves is discussed.

ISSN:0031-9171    

DOI:10.1063/1.1694215

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The resonant interaction of a triad of inertial waves is investigated theoretically. An additional condition for resonance is found to be necessary compared to short internal wave interactions—namely, that the polarization must be specified. One of the quantities conserved is&ohgr;· ucalculated for each wave separately and summed over the triad. Here,&ohgr;is the vorticity field anduis the velocity field of the inertial wave. Resonance diagrams are given and two explicit examples of amplitude variations are calculated.

ISSN:0031-9171    

DOI:10.1063/1.1694216

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An experimental study was made of the instability of an accelerated water‐air interface. The measured growth rate agreed with theory. The method of analysis of the data reduced scatter in the results and allowed the growth rate of second order waves to be determined. The growth rate of second‐order waves agreed reasonably well with theory of Emmons, Chang, and Watson.

ISSN:0031-9171    

DOI:10.1063/1.1694217

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A theoretical relation has been obtained for the mass flux to a rotating disk in a non‐Newtonian fluid which includes the convective transport in the radial direction. This result has then been used to obtain improved values for the diffusivities of oxygen in aqueous sodium chloride solutions which were rendered non‐Newtonian by addition of Polyox WSR 301.

ISSN:0031-9171    

DOI:10.1063/1.1694218

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Measurements were taken of the heat transport and vertical component of the fluid velocity in a horizontal layer of water heated from below. The heat transfer results were well correlated by a simple power law relationship and indicated the possibility of flow transitions even at relatively high Rayleigh numbers. The velocity measurements were obtained optically and compared to predictions of Kraichnan.

ISSN:0031-9171    

DOI:10.1063/1.1694219

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Asymmetric distribution of interfacial mass fluxes is responsible for diffusion drag. Its contribution to over‐all drag is appreciable for strongly circulating drops and less so for noncirculating ones. Both self‐similar and uniformly distributed interfacial fluxes cause the separating stream line to detach from the interface.

ISSN:0031-9171    

DOI:10.1063/1.1694220

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A study is made of the flow which results when an initially uniform gas expands into a vacuum through a complete one‐dimensional rarefaction wave, and then strikes either a solid wall or a similar opposite facing rarefaction. A Knudsen numberK nis defined by the ratio of the undisturbed mean free path to the distance between the center of the rarefaction and the wall. The direct simulation Monte Carlo method has been used to obtain numerical solutions over a range ofK nfrom 10−4to 103. Results for the wall pressure profile were also obtained from experiment and from approximate continuum calculations. The pressure profile on the wall or the line of symmetry was found to be insensitive to assumptions about the initial highly rarefied stage of the reflection. On the other hand, when considering the temperature history of the gas adjacent to the wall, a proper molecular analysis of the initial stage of reflection was required for all values of the Knudsen number.

ISSN:0031-9171    

DOI:10.1063/1.1694221

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The electrical conductivity, the translational, reactive, and internal thermal conductivity and the viscosity have been calculated for nitrogen at 1‐atm pressure and temperatures from 5000‐35 000°K. Generally satisfactory agreement is noted between the properties as computed and measured in the electric arc.

ISSN:0031-9171    

DOI:10.1063/1.1694222

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A weakly ionized argon gas flows in a 2 cm diam tube at 60‐100 m/sec velocities and at mean pressures of 20‐50 Torr, producing turbulence in the channel with Reynolds numbers ranging from 2000 to 6000. One‐dimensional turbulence spectra are detected by laser interferometry and Langmuir probes. The experimental results obtained by these two methods show a new region between the Kolmogoroff and the dissipation region where the spectrum of both the neutrals and the ions vary ask −13/3(wherekis the wave number). It is concluded that this intermediary region is associated with fluid effects rather than being a consequence of ambipolar diffusion of particles in the plasma as has been suggested. Furthermore, it is suggested that compressibility may be responsible for the intermediary region of turbulence spectra.

ISSN:0031-9171    

DOI:10.1063/1.1694223

出版商:AIP    

年代:1973

数据来源: AIP