We analyse acoustic streaming flows using an arbitrary Lagrangian Eulerian (ALE) perspective. The formulation stems from an explicit separation of time scales resulting in two subproblems: a first-order problem, formulated in terms of the fluid displacement at the fast scale, and a second-order problem, formulated in terms of the Lagrangian flow velocity at the slow time scale. Following a rigo...

The analysis of unsteady fluid flows on moving domains is a very complex task, that may be often tackled using domain remeshing techniques. In the present paper a novel mesh movement strategy is presented. It is based on the blending of simple local edge-swapping with mesh deformation by means of the elastic analogy. To deal with mesh topology changes an extension of the classical Arbitary Lagr...

Despite the improvements in prevention of acute respiratory disease in preterm infants, the incidence of bronchopulmonary dysplasia (BPD) remains largely unchanged. Acquired lobar emphysema (ALE) is an increasingly recognized complication of advanced BPD. Barotrauma, oxygen toxicity and lung immaturity are presumed to play an important role in the development of ALE in children with BPD and mos...

Though most engineering problems in acoustics directly deal with the wave equation in its irreducible form, in many situations it becomes interesting to consider it in mixed form [1], so as to directly account for both, the acoustic pressure and the acoustic velocity fields. A particular case is that of waves propagating in domains with moving boundaries. When attempting a finite element soluti...

A new geometrically conservative arbitrary Lagrangian-Eulerian (ALE) formulation is presented for the moving boundary problems in the swirl-free cylindrical coordinates. The governing equations are multiplied with the radial distance and integrated over arbitrary moving Lagrangian-Eulerian quadrilateral elements. Therefore, the continuity and the geometric conservation equations take very simpl...

We present a monolithic geometric multigrid solver for fluid-structure interaction problems in Arbitrary Lagrangian Eulerian coordinates. The coupled dynamics of an incompressible fluid with nonlinear hyperelastic solids gives rise to very large and ill conditioned systems of algebraic equations. Direct solvers usually are out of question due to memory limitations, standard coupled iterative so...

In this contribution we investigate a monolithic algorithm to solve the problem of time dependent interaction between an incompressible, possibly nonnewtonian, viscous fluid and an elastic solid. The continuous formulation of the problem and its discretization is done in a monolithic way, treating the problem as one continuum and discretized by the Q2/P1 finite elements. The resulting set of no...

Adaptive laboratory evolution (ALE) under controlled conditions has become a valuable approach for the study of the genetic and biochemical basis for microbial adaptation under a given selection pressure. Conventionally, the timescale in ALE experiments has been set in terms of number of generations. As mutations are believed to occur primarily during cell division in growing cultures, the cumu...

The aim of this paper is to study the feasibility of using (irreversible) entropy production as driving force for a moving mesh. Such a method should be able to capture or track physical phenomena such as viscous and thermal boundary layers, shock waves and regions with chemical reactions. A brief outline is given for the FEM-ALE approach, which forms the basis of the moving mesh method. Mesh v...