摘要:

The shape and speed of a pair of touching finite area vortices are calculated and an error in previous work corrected.

ISSN:0031-9171    

DOI:10.1063/1.863679

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Laboratory experiments have been conducted in which a spherical solid obstacle has been towed steadily through a thermally stratified rotating fluid in order to determine the effects of the density‐profile shape upon the attenuation with height of the disturbance produced by the obstacle. The existence of a cutoff level in the fluid beyond which the disturbance is not detected is illustrated, and the dependence of this level upon local variations in density profile is studied. Measurements of velocity above and behind the obstacle are reported.

ISSN:0031-9171    

DOI:10.1063/1.863680

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A jet of viscous fluid falling against a flat plate may become unstable and buckle. The buckling process is postulated as a discontinuity, and a simple model is developed that indicates a loss of energy in the fluid buckling. Experimental values of the energy loss coefficient are presented.

ISSN:0031-9171    

DOI:10.1063/1.863681

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Subharmonic generation has been observed during the propagation of deep‐water capillary waves. The observations are shown to be in agreement with the theory of degenerate resonant noncollinear three‐wave interaction in a nonlinear, dispersive medium.

ISSN:0031-9171    

DOI:10.1063/1.863682

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

It is shown that an inviscid, incompressible liquid completely filling a finite, sectored, rapidly rotating cylinder, possesses a continuous inertial wave frequency spectrum rather than the usual denumerably infinite set of frequencies! A physical argument for this unusual phenomenon is presented along with reference to some confirmatory experiments.

ISSN:0031-9171    

DOI:10.1063/1.863683

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An exact analytical solution for the velocity field, both interior and exterior, induced by an infinite right‐handed helical vortex filament is derived. Due to the way the variables combine in this solution, the paper also shows that it is possible to derive a stream function for this nonaxisymmetric flow. Sample calculations of these expressions are included.

ISSN:0031-9171    

DOI:10.1063/1.863684

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An asymptotic theory is developed to describe the stability characteristics of a swirling axial flow at high Reynolds numberRwhen subject to disturbances with a large azimuthal wavenumbern. It is based on an earlier study by Leibovich and Stewartson of the corresponding inviscid problem. The essence of the theory is to exploit the fact that the disturbance is concentrated on a narrow band at a finite distance from the axis decaying exponentially on either side. As an example to illustrate the theory, the stability characteristics of a trailing vortex is examined. A comparison with computed values of the neutral curves forn=1,2,3 shows that even at such low values ofnthe theory is generally qualitatively correct and in some respects is remarkably accurate. UFoff

ISSN:0031-9171    

DOI:10.1063/1.863685

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

It is demonstrated that the perturbation equation governing small disturbances in an Ekman boundary layer possesses a double branched, continuous spectrum of temporal eigenvalues. The nature of these eigenvalues and their associated eigenfunctions is discussed and compared with that of the temporal spectrum of the Blasius boundary layer.

ISSN:0031-9171    

DOI:10.1063/1.863686

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Available data for the turbulent wake of unheated and heated cylinders are compared to far‐wake solutions obtained from the relevant equations prior to application of any closure assumption. It is found that such comparisons require a new determination of the virtual origin significantly different from traditional values and at the same time provide a sensitive criterion to decide if the stations at which data are collected are sufficiently far downstream for far‐wake solutions to apply.

ISSN:0031-9171    

DOI:10.1063/1.863687

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A strong explosion occurring on a flat ground generates a blast wave behind which an unsteady boundary layer sets in. It is shown that when the ground is insulated the boundary layer develops a self‐similar structure and its thickness does not depend directly on time to the first approximation.

ISSN:0031-9171    

DOI:10.1063/1.863688

出版商:AIP    

年代:1982

数据来源: AIP