Multiscale Computational Fluid Dynamics

Abstract

Computational Fluid Dynamics (CFD) has numerous applications in the field of energy research, in modelling the basic physics of combustion, multiphase flow and heat transfer; and in the simulation of mechanical devices such as turbines, wind wave and tidal devices, and other devices for energy generation. With the constant increase in available computing power, the fidelity and accuracy of CFD simulations have constantly improved, and the technique is now an integral part of research and development. In the past few years, the development of multiscale methods has emerged as a topic of intensive research. The variable scales may be associated with scales of turbulence, or other physical processes which operate across a range of different scales, and often lead to spatial and temporal scales crossing the boundaries of continuum and molecular mechanics. In this paper, we present a short review of multiscale CFD frameworks with potential applications to energy problems.

Multiscale Eulerian CFD of Chemical Processes: A Review

“…Many scientific problems have intrinsically multiscale nature [1,2]. This multiscale nature often leads to multiple spatial and temporal scales that cross the boundaries of continuum and molecular levels [3]. Multiscale simulations cover quantum mechanics, molecular dynamics (MD), coarse-grained particle dynamics, and continuum mechanics [4,5].…”

“…The fundamental idea of LBM is that the macroscopic dynamics of a fluid are the result of the collective behavior of many microscopic particles in the system [19]. Thus, by integrating the particle momentum space, the particle distribution function (Boltzmann transport equation) at the microscopic scale is linked to the continuous fluid dynamic properties such as density, velocity, and energy at the macroscopic scale [3,20]. LBM is an alternative approach in CFD, which has been applied to fluid flows in porous media, microfluidics, and particulate flows [19,20].…”

“…Fluid dynamics are governed by the Navier-Stokes (NS) equation representing the conservation of momentum. Turbulence is involved in the NS equation to consider random fluctuations of fluid motion [3]. There are several turbulence equations, such as the direct numerical simulation (DNS), large eddy simulation (LES) [30], and Reynolds-averaged Navier-Stokes (RANS)-based k-ε models.…”

“…Multiphase physics is omnipresent in both environmental and engineering flows [32]. As the precision and accuracy of manufacturing techniques progress, micro-and nanotechnologies become crucial for providing engineering solutions to problems across different industrial sectors [3]. The multiscale CFD approach has been applied to various disciplines for more accurate solutions than can be obtained using single-scale modeling.…”

“…The behavior of the macroscale flow is affected by microscale physical processes, which also leads to multiscale CFD modeling [3]. Multiscale behavior with complex physical phenomena, which are highly interrelated [17], appears in process engineering.…”