Phase‐resolving direct numerical simulations of particle transport in liquids—From microfluidics to sediment

Abstract

The article describes direct numerical simulations using an Euler–Lagrange approach with an immersed‐boundary method to resolve the geometry and trajectory of particles moving in a flow. The presentation focuses on own work of the authors and discusses elements of physical and numerical modeling in some detail, together with three areas of application: microfluidic transport of spherical and nonspherical particles in curved ducts, flows with bubbles at different void fraction ranging from single bubbles to dense particle clusters, some also subjected to electro‐magnetic forces, and bedload sediment transport with spherical and nonspherical particles. These applications with their specific requirements for numerical modeling illustrate the versatility of the approach and provide condensed information about main findings.

Preface to special issue on Direct numerical simulations of turbulent flows—Part II

“…Finally, Froehlich et al [3] present an overview of the immersed boundary method (IBM) applied to the computation of particle‐ and bubble‐laden flows. The IBM is an Euler–Lagrange approach which allows to directly impose interphase coupling conditions (such as no‐slip/no‐penetration) at the interface between two phases in an efficient, accurate and relatively simple way.…”

“…The IBM is an Euler–Lagrange approach which allows to directly impose interphase coupling conditions (such as no‐slip/no‐penetration) at the interface between two phases in an efficient, accurate and relatively simple way. Froehlich et al [3] focus their description of the numerical procedure, which builds upon on the seminal work of Uhlmann [11], on the treatment of the nonslip interface condition, the computation of the hydrodynamic forces driving the particle motion, and the important topic of the treatment of light particles [7]. The authors show the capabilities of their approach by simulating flows of notable complexity, including particles in microfluidic systems, bubble dynamics in liquid metals with superimposed electro‐magnetic fields and pattern formation in polymorph and poly‐disperse sedimentary flows.…”

“…For a brief introduction to DNS, the reader is referred to the preface of the preceding issue [1], and references therein. The two issues contain a broad spectrum of topics which includes the study of sound generation mechanisms in combustion [4], the extraction of dominant spatiotemporal patterns and coherent structures in several canonical flows [12,14], the active control of turbulence in compressible fluid flows [9], the modeling of jets impinging on rough surfaces [10], the high-order, low-dissipation modeling of compressible multi-phase flows [2] and the accurate simulation of particle-and bubble-laden fluid flows [3]. In what follows, we briefly summarize the three contributions to the second issue.Flows driven by pressure gradients and by temperature-induced buoyancy forces are referred to as mixed convection flows and are common in nature and in engineering, for example, in heat exchangers, cooling systems, and air-conditioned rooms and spaces, such as an airplane cabin.…”