Flow Past Bodies Research Articles

Use of the splitting method to solve problems of the dynamics of a viscous incompressible fluid

A NUMERICAL method of solving problems of the dynamics of a viscous incompressible fluid, using the splitting of the non-stationary equations of motion, first proposed by Harlow and Chorin is considered. Unlike methods of the MAC type and its modifications (SMAC, MACRL, ALE etc), the difference scheme of the proposed method enables us to calculate flows without using the boundary condition for the vortex or the pressure on the solid surface. Some results of numerical calculations of the flow past bodies of finite dimensions are given which illustrate the possibilities of the method.

The legendre condition in optimum problems of supersonic gasdynamics: PMM vol. 39, n≗ 6, 1975, pp. 1032–1042

The necessary Legendre condition for problems of optimum (in the sense of minimum wave drag) supersonic flow past bodies is obtained. Plane and axisymmetric flows are considered on the assumption of imposition of isoperimetric constraints of a general form. Shock-free flows and flows with attached shock waves are investigated. The method here proposed is used for deriving the second order condition in the particular case when it is possible to pass to the reference contour, and which has been earlier obtained by Shmyglevskii [1] and then by Guderley and others [2].

VORTEX: A quasi-steady supermagnetosonic rotating plasma experiment

A rotating plasma experiment has been built which produces a stable, reproducible, super-magnetosonic flow in highly ionized argon. The rotation is produced by a radial electrical discharge across a vertical magnetic field. A preheat discharge gives uniform starting conditions for the flow. The flow velocity exceeds the limit predicted for argon by the Alfven critical velocity theory. Magnetosonic mach numbers up to 2.0 and flow times of 0.5 msec are obtained. The VORTEX plasma is used to model some aspects of the solar wind flow past bodies in the solar system.

Analytical study of the heat transfer in a longitudinal flow past cylindrical bodies of small radius at constant temperature

We obtain over a wide range of curvature parameters the analytical dependence of the heat transfer in a longitudinal flow past cylindrical bodies of small radius at constant temperature.

On hypersonic flow past conical segment bodies at large angle of attack

On hypersonic flow past conical segment bodies at large angle of attack

A free-streamline theory for bluff bodies attached to a plane wall

A free-streamline theory is presented for the separated flow past two-dimensional bluff bodies attached to a long plane wall on which a turbulent boundary layer has developed. The non-uniform velocity profile in the turbulent boundary layer which would be measured if the bluff bodies were absent has been replaced by a hypothetical inviscid parallel shear flow which has a constant vorticity. This model admits analytical solutions and automatically yields closed streamlines in front of the bluff bodies such as the normal plate and the semicircular projection, which are geometrically very similar to observed front separation bubbles. The present theory involves three or four parameters which must be determined on the basis of experimental information, the number of parameters depending upon the shape of bluff bodies. Two typical examples of bluff bodies, i.e. the normal plate and the semicircular projection, are worked out. Pressure distributions around these bodies predicted by the present theory are found to give a good agreement with experimental measurements.

Surface Vorticity Theory for Axisymmetric Potential Flow past Annular Aerofoils and Bodies of Revolution with Application to Ducted Propellers and Cowls

The well known surface vorticity method originally due to Martensen for calculating two-dimensional aerofoil and cascade flows is extended to axisymmetric flows past annular aerofoils, bodies of revolution and interacting combinations of these. A variety of solutions is presented in comparison with experimental test or classical solutions. A generalized surface vorticity integral equation for fully three-dimensional flow is developed in curvilinear co-ordinates from which the two-dimensional axisymmetric equations are shown to be reducible. This paper is aimed at ship ducted propeller problems but is of wider application to fan cowls, nozzles, bodies of revolution or engine intakes.

Effect of nose shape on hypersonic flow past slender blunt bodies at an angle of attack

We examine some characteristics of hypersonic flow past slender blunt bodies of revolution at a small angle of attack α≲τ≪1, where τ is the relative body thickness. It is shown that, within the framework of hypersonic theory, for a correct-consideration of the effect of the conditions in the transitional section between the nose and the lateral surface it is necessary, in the general case, to specify the circumferential distribution of the force effect for the nose and the mass of the gas. For small α, the effect of the nose, just as in two-dimensional flows [1–4], shows up only through its drag coefficient cx, for α=0. On this basis, the similarity law [1–4] for flow past such bodies, with arbitrary form of the lateral surface and differing in the shape of the nose blunting, which is valid over the entire disturbed region, with the exception of a small vicinity of the nose, is extended to the case in question.

Method of curved bodies in problems of unsteady hypersonic flow past slender bodies

The method of curved bodies involves replacing the unsteady flow past a body by steady flow past a different body obtained from the original body by suitable curvature of its form. The idea of the method was proposed by Vetchinkin in 1918 and was first carried out in [1]. Here the authors started from the assumption that the pressure on the body surface is determined only by its local angle of attack.

Transonic flow past slender bodies

Transonic flow past slender bodies

Hypersonic flow past ducted blunt bodies of revolution

Chernyi [1, 2] has examined the problem of hypersonic flow past a ducted cone with sharp leading edge. In the following we present an analysis of the characteristic features of this problem in the case of a blunt leading edge.

Experimental study of vortex flow past smooth, winged, and ribbed bodies of revolution at M=2

Experimental study of vortex flow past smooth, winged, and ribbed bodies of revolution at M=2

Shock-layer thickness for supersonic viscous gas flow past blunt bodies

Shock-layer thickness for supersonic viscous gas flow past blunt bodies

Stagnation point location for three-dimensional hypersonic flow past segmental bodies

Stagnation point location for three-dimensional hypersonic flow past segmental bodies

Calculation of three-dimensional unsteady hypersonic gas flow past slender blunt bodies

Calculation of three-dimensional unsteady hypersonic gas flow past slender blunt bodies

Supersonic flow past axisymmetric flared cones

Systematic data on the determination of the aerodynamic characteristics of axisymmetric bodies with a break in the generating line (Fig. 1a, b) in supersonic flow at zero angle of attack are presented in [1, 2, and others]. A characteristic feature of the flow past such bodies is the appearance of an extensive separation zone dec in the region of the break in the generator when the break angle exceeds some minimum value δ∘≥δmin, which for a turbulent boundary layer depends basically on the Mach number M at the body surface ahead of the separation zone. In this case, compression waves which change into the oblique compression shocks dc′ and cc′, emanate both from the beginning of the separation zone (point c) and from the end of it (point d). These shocks, intersecting at the point c′, form the triple shock configuration ac′d and ac′c for which we introduce the notationac′[c, d]. The maximum value (δmax) of the generator break angle is limited by the possibility of the existence of an attached compression shock, dc′. According to these data a change in the generator break angle for the range δmin≤δ∘≤δmax of the angle does not disrupt the nature of the flow in the separation zone, but only alters the size of this zone.

Irrotational flow past bodies close to a plane surface

A theroetical analysis is given for potential flow over, around and under a vehicle of general shape moving close to a plane ground surface. Solutions are given both in the form of a small-gap asymptotic expansion and a direct numerical computation, with close agreement between the two for two-dimensional flows with and without circulation. Some results for three-dimensional bodies are discussed.

The Hypersonic Source Flow Past Wedges and Cones

SummaryTo study the effects of flow non-uniformities on the hypersonic flow past test bodies, perturbation analysis is applied to the hypersonic source flow past wedges and cones. In both cases it is shown that the effects of the source flow on the shock shape and velocity are small, while effects on the pressure and density are large. Curves are presented for various values of the Mach number from which these effects can be estimated.

Vortex shedding from a turbulent jet in a cross-wind

Measurements in the wake behind turbulent jets exhausting from a solid surface into a cross-wind indicate that vortex shedding occurs as in the case of flow past solid bluff bodies. The Strouhal numbers for flow past a circular and a blunt jet are in qualitative agreement with those for corresponding solid bodies, provided that the width of the spreading jet some distance from the surface is used rather than the jet exit plane dimension.

A solution for hypersonic flow past slender bodies

A solution to the hypersonic small disturbance equations is obtained for a class of two-dimensional bodies supporting logarithmic shock waves by reducing the partial differential equation to an ordinary differential equation. The body shape is calculated and shown not to be logarithmic if γ ≠ 1, where γ is the ratio of the specific heats of the gas.