A method is proposed for computing the low-Reynolds-number hydrodynamic forces on particles comprising a suspension confined by two parallel, no-slip walls. This is constructed via the two-dimensional analogue of Hasimoto’s solution (J. Fluid Mech., vol. 5, 1959, pp. 317–328) for a periodic array of point forces in a viscous, incompressible fluid, and, like Hasimoto, the summation of interactio...

This paper presents the application of a recently proposed ‘second-order’ homogenization method (J. Mech. Phys. Solids 50 (2002) 737–757) to the estimation of the effective behavior of hyperelastic composites subjected to finite deformations. The main feature of the method is the use of ‘generalized’ secant moduli that depend not only on the phases averages of the fields, but also on the phase ...

In this paper, we derive a general relationship for the turbulent Prandtl number Pr t for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Pr t , is developed in terms of a mixing length scale LM and an overturning length scale LE , the ratio of the mechanical (turbulent kinetic energy) deca...

The computational efficiency of random field representations with the Karhunen-Loève expansion relies on the numerical solution of a Fredholm integral eigenvalue problem. In this contribution, different methods for this task are compared. These include the finite element method (FEM), the finite cell method (FCM) and the Nyström method. For the FEM with linear basis functions, two different app...

The time development of ripples under sea waves is investigated by means of the weakly nonlinear stability analysis of a flat sandy bottom subjected to the viscous oscillatory flow that is present in the boundary layer at the bottom of propagating sea waves. Second-order effects in the wave steepness are considered, to take into account the presence of the steady drift generated by the surface ...

In a fluid system in which two immiscible layers are separated by a sharp free interface, there can be strong coupling between large amplitude nonlinear waves on the interface and waves in the overlying free surface. We study the regime where long waves propagate in the interfacial mode, which are coupled to a modulational regime for the freesurface mode. This is a system of Boussinesq equation...

Only limited information is currently available on the evolution of waves generated by wind that varies in time, and in particular on the initial stages of wind–wave growth from rest under a suddenly applied wind forcing. The emerging wind–wave field varies in time as well as in space. Detailed knowledge of wave parameter distributions under those conditions contributes to a better understandin...

Many modern databases include personal and sensitive cor-related data, such as private information on users connectedtogether in a social network, and measurements of physicalactivity of single subjects across time. However, differentialprivacy, the current gold standard in data privacy, does notadequately address privacy issues in this kind of data.This work looks at a ...

We present a combined analytical and numerical study of the instabilities of a pair of parallel unequal-strength vortices. We extend the analyses of a vortex in an external strain field (Crow, AIAA J. vol. 8, 1970, p. 2172; Widnall et al., J. Fluid Mech. vol. 66, 1974, p. 35) to include the orbital motion of the vortex pair. For counter-rotating pairs, the classic Crow-type periodic displacemen...

The quasi-steady migration and deformation of bubbles rising in a wall-bounded linear shear flow are investigated experimentally in the low-but-finite-Reynolds-number regime. A travelling optical device that follows the bubble is used for this purpose. This apparatus allows us to determine accurately the bubble radius, contour and rising speed, together with the distance between the bubble and ...