The motion of a body with a deformable surface in an ideal incompressible liquid

Averbukh, A. Z.

doi:10.1007/bf01017549

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a rigid body in steady flow represented by multipoles of arbitrary order, (10) and (1 1) are identical with the corresponding equations given in Landweber (1967). For the case of a deformable surface moving in an unbounded fluid, the generalized Lagally expressions reduce to the form given in Averbukh (1973) in terms of added-mass coefficients. Equations (10) and (11) are more general in the sense that they apply to a general unsteady motion of deformable or permeable bodies which are represented by multipoles of arbitrary order.…”

Section: Jy (51)mentioning

confidence: 99%

Unsteady Lagally theorem for multipoles and deformable bodies

Landweber

Miloh

1980

J. Fluid Mech.

View full text Add to dashboard Cite

The Lagally theorem for unsteady flow expresses the forces and moments acting on a rigid body moving in an inviscid and incompressible fluid in terms of the singularities of the analytically continued flow within the body. Previous generalizations of the Lagally theorem, originally given by Lagally (1922) for steady flows, are due to Cummins (1957) and Landweber & Yih (1956), who consider the effect of flow unsteadiness on the forces and moments. In these, the system of image singularities within the body was assumed to consist of isolated or continuous (surface or volume) distributions of sources and doublets. A further extension of Lagally's theorem ie due to Landweber (1967), who derived expressions for the steady forces and moments acting on a rigid body generated by isolated or a continuous distribution of multipoles. The purpose of the present paper is to generalize the Lagally theorem so as to include the effects of multipoles in unsteady flow, and deformability of the body, as well as to present a briefer derivation of the resulting formulae. Two examples, illustrating the application of the force and moment formulae, will be presented.

show abstract

Section: Jy (51)mentioning

confidence: 99%

Unsteady Lagally theorem for multipoles and deformable bodies

Landweber

Miloh

1980

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…The hydrodynam ical forces and moments acting on a deformable body moving in an unbounded fluid, may be expressed in term s of the Kelvin impulse and impulsecouple of the motion (Averbukh 1971;Wu 1975; see also Blake 1988;Oguz & Prosperetti 1990). Still another alternative, which seems to be more appropriate for the present case, is using the generalized Lagally theorem for deformable bodies (Landweber & Miloh 1980), as discussed in Miloh (1983Miloh ( , 1991.…”

Section: General Formulationmentioning

confidence: 99%

Self-propulsion of general deformable shapes in a perfect fluid

Miloh

Galper

1993

Proc. R. Soc. Lond. A

View full text Add to dashboard Cite

We consider the hydrodynamical problem of a general three-dimensional smooth deformable body moving in a perfect fluid, which undergoes arbitrary continuous temporal variations in its shape. Special attention is payed to the phenomena of selfpropulsion (translation and rotation) of such a shape and reference is made to the dynamics of non-spherical deformable bubbles, cavities and drops. Some distinctive cases, in which the method can be applied to impulsively started highly-vibrating rigid surfaces, are also presented. The Lagally theorem for deformable surfaces, is applied to determine the induced velocity of self-propulsion. The general deformation is assumed to consist of a large scale volume-mode and superposed small scale shapemodes. The time-averaging procedure is introduced and the effect of persistent self-propulsion is shown to be generated as a result of nonlinear interactions between these modes, which must preserve certain skew-symmetric and phase-difference properties. It is proven that, as a result of perfect symmetry, a spherical shape is a degenerate and an inefficient self-propulsor. The results are demonstrated for prolate (oblate) spheroidal shapes and simplified expressions are obtained as limiting cases for spherical, rod-like (slender) and circular disc shapes.

show abstract

The motion of a body with a deformable surface in an ideal incompressible liquid

Cited by 2 publications

References 0 publications

Unsteady Lagally theorem for multipoles and deformable bodies

Unsteady Lagally theorem for multipoles and deformable bodies

Self-propulsion of general deformable shapes in a perfect fluid

Contact Info

Product

Resources

About