Experiments on the flow past an inclined disk

Abstract

The wake of a disk at an angle to a stream contains marked periodic motions which arise from the regular shedding of vortices from the trailing edge. The vortices are in the form of a chain of irregular rings, each one linked to the succeeding one, and they move downstream at about 0·6 of free-stream velocity. The prominence of the vortex shedding increases as the angle of incidence (measured from the normal) increases up to at least 50°. The shedding frequency increases with the angle of incidence, but by a suitable choice of reference velocity and length scale, may be described by a wake Strouhal number which has the constant value 0·21 for all angles of incidence above zero, up to at least 40°.Axially-symmetric bodies at zero incidence shed vortices in a similar manner, except that the orientation of the plane of vortex shedding is not fixed and varies from time to time.

Stability to Finite Disturbances: Energy Method and Landau’s Equation

“…2.2 it was mentioned that the dependence of the drag of a sphere submerged in a fluid flow on the Reynolds number Re was studied long ago by Eiffel (1912) and Prandtl (1914) (in fact there were also many other early studies of sphere drag); all these studies inevitably included the consideration of sphere wakes. The formation of vortices behind a sphere and vortex shedding from spheres were described in the 1930s in particular by Winny (1932); Foch andChartier (1935), andMöller (1938), while later the vortical structures and quantitative characteristics of sphere wakes were studied by Taneda (1956Taneda ( , 1978; Torobin and Gauvin (1959); Magarvey and Bishop (1961a, b); Magarvey and MacLatchy (1965); Goldburg and Florsheim (1966); Zikmundova (1970);List and Hand (1971);Calvert (1972);Masliyah (1972); Achenbach (1972Achenbach ( , 1974; Nakamura (1976); Pao and Kao (1977); Perry and Lim (1978); Kim and Durbin (1988); Haniu (1990, 1995); Berger et al (1990); Bonneton and Chomaz (1992); Wu and Faeth (1993);Provansal (1996); Provansal and Ormières (1998); Ormières et al (1998); Ormières and Provansal (1999), and many other experimenters. Nevertheless experimental data for sphere wakes continue to be scattered and sometimes contradictory.…”

The naturally oscillating flow emerging from a fluidic precessing jet nozzle

“…If the patterns are interpreted as skin-friction lines, corresponding to a continuous velocity field, certain topological rules can be applied to a limited number of singular points observed on the surface of the object (Tobak & Peake 1979). This implies that only the leeward surfaces of a disk by Calvert (1967) and a disk-wing, or a 'Frisbee' (Nakamura & Fukamachi 1991;Potts & Crowther 2000) both inclined at an angle to a free stream, and a coin-like cylinder (Zdravkovich et al 1998) parallel to the free stream. (e) two foci to the left-and right-hand side of the secondary stagnation point; and (f ) some evidence of saddle points associated with the foci.…”

A composite cavity model for axisymmetric high Reynolds number separated flow I: modelling and analysis

“…The i m p o r t a n t points to note about the log e---~ -~ limit concern the role of the integral in (5) and the behaviour near the end points of the cavity, and the dimensionality. First, we saw in section 3.3 how the solution to the full integral equation (5) has…”

“…Such constant pressure cavities (Helmholtz-Kirchhoff models) are a common modelling assumption for separated flows (see, for example Levinson (1946) for the asymptotic behaviour of an infinite cavity far downstream) and are often observed in experimental results for two-dimensional flow down a step. For axisymmetric flows the reader is referred to Calvert (1967) and Presz & Pitkin (1974) for experimental pressure profiles. Although these experiments were conducted at O(1) subsonic Mach numbers or using O(1) geometries, the downstream pressure distribution shows qualitative agreement with incompressible two-dimensional flows.…”