Mesoscopic Methods in Engineering and Science

(First paragraph) Matter, conceptually classified into fluids and solids, can be completely described by the microscopic physics of its constituent atoms or molecules. However, for most engineering applications a macroscopic or continuum description has usually been sufficient, because of the large disparity between the spatial and temporal scales relevant to these applications and the scales of the underlying molecular dynamics. In this case, the microscopic physics merely determines material properties such as the viscosity of a fluid or the elastic constants of a solid. These material properties cannot be derived within the macroscopic framework, but the qualitative nature of the macroscopic dynamics is usually insensitive to the details of the underlying microscopic interactions

Numerical wave flume with Lattice Boltzmann Method for Wave Energy Converters

Based on Lattice Boltzmann Method, a free interface tracking model using volume of fraction (VOF) technique is built to explore the interaction of Oscillating Water Column (OWC) type of Wave Energy Converters (WECs) with waves. In the numerical wave flume, the momentum source is applied to generate incident waves and absorb reflected waves. After validation, one stationary OWC in the absence of Power take-off system (PTO) is then placed in the numerical wave flume to examine the performance of the numerical scheme. The simulation results show that the numerical stability is well achieved with the wave-structure interaction included and there is a strong vortex shedding at wall corner and nonlinearity with smaller amplitude in the present viscous flow model, compared with the linear potential flow solution

A next-generation CFD tool for large-eddy simulations on the desktop

Dive deep into the fascinating world of real-time computational fluid dynam- ics. We present details of our GPU-accelerated flow solver for the simulation of non-linear violent flows in marine and coastal engineering. The solver, the efficient lattice boltzmann environment elbe, is accelerated with recent NVIDIA graphics hardware and allows for three-dimensional simulations of complex flows in or near real-time. Details of the very ef- ficient numerical back end, the pre- and postprocessing tools and the integrated OpenGL visualizer tool will be discussed. Moreover, several applications with marine relevance demonstrate that elbe can be considered as prototype for next-generation CFD tools for simulation-based design (SBD) and interactive flow field monitoring on commodity hardware

A Parallel Coupled Lattice Boltzmann-Volume of Fluid Framework for Modeling Porous Media Evolution

In this paper, we present a framework for the modeling and simulation of a subset of physical/chemical processes occurring on different spatial and temporal scales in porous materials. In order to improve our understanding of such processes on multiple spatio-temporal scales, small-scale simulations of transport and reaction are of vital importance. Due to the geometric complexity of the pore space and the need to consider a representative elementary volume, such simulations require substantial numerical resolutions, leading to potentially huge computation times. An efficient parallelization of such numerical methods is thus vital to obtain results in acceptable wall-clock time. The goal of this paper was to improve available approaches based on lattice Boltzmann methods (LBMs) to reliably and accurately predict the combined effects of mass transport and reaction in porous media. To this end, we relied on the factorized central moment LBM as a second-order accurate approach for modeling transport. In order to include morphological changes due to the dissolution of the solid phase, the volume of fluid method with the piece-wise linear interface construction algorithm was employed. These developments are being integrated into the LBM research code VirtualFluids. After the validation of the analytic test cases, we present an application of diffusion-controlled dissolution for a pore space obtained from computer tomography (CT) scans

Lattice Boltzmann Method For Multiphase Flows With High Density Ratios

This thesis describes the Lattice Boltzmann Method (LBM) and its application to single and multiphase flows. The LBM algorithm using Single Relaxation Time (SRT) and Multi Relaxation Time (MRT) models are studied. In particular, a new MRT multiphase model is developed, based upon the SRT multiphase model of Banari et al. (2014). A unified LBM approach is used with separate formulations for the phase field, the pressureless Naiver-Stokes (NS) equations and the correction of the pressureless velocity field by solving a Poisson equation. To validate the current model, computations for various Reynolds numbers (Re) were performed to simulate 2D lid driven cavity flow. Results show excellent comparison with those in the literature. The multiphase model was verified with two fluid Poiseuille flow, static and rising bubbles. The method was also used to simulate 2D single and multiple mode Rayleigh-Taylor instability (RTI). A good comparison between the present numerical results and those in the literature at large Re with high density ratio and various values of surface tension coefficient in single mode and multiple mode RTI are made, respectively. The multiphase LB model has been extended using MRT collision operator to study various breaking dam problems with both dry and wet bed, expanding the range of the possible density ratios and Re which was impossible with SRT. The simulations show agreement with those in the literature. Moreover, grid convergence was studied using both acoustic and diffusive scaling for standing wave simulations with high density ratios. The use of MRT was found to improve the stability for high density ratio. Results with density ratio up to 1000 at large Re = 1000 were obtained using MRT model.Iraqi Ministry of Higher Education and Scientific Research (MOHESR

Proceedings of the Cardiff University Engineering Research Conference 2023

The conference was established for the first time in 2023 as part of a programme to sustain the research culture, environment, and dissemination activities of the School of Engineering at Cardiff University in the United Kingdom. The conference served as a platform to celebrate advancements in various engineering domains researched at our School, explore and discuss further advancements in the diverse fields that define contemporary engineering

The research on mechanical properties and compressive behavior of graphene foam with multi-scale model?

Computational simulation is an effective method to study the deformation mechanism and mechanical behaviour of graphene-based porous materials. However, due to limitations in computational methods and costs, existing research model deviate significantly from the real material in terms of the scale of structure. Therefore, building a highly accurate computational model and maintaining an appropriate cost is both necessary and challenging. This paper proposed a multi-scale modelling approach for finite element (FE) analysis based on the concept of structural hierarchy. The stochastic feature of the microstructure of porous materials are also considered. The simulation results of the regular structure model and the Voronoi tessellation model are compared to investigate the effect of regularity on the material properties. Despite some shortcomings, other microstructural features of porous graphene materials can be gradually introduced to improve the material model step by step. Thus the developed multiscale model has great potential to simulate the properties of materials with mesoscopic size structure such as graphene foam (GF)