Volume of fluid method

About: Volume of fluid method is a research topic. Over the lifetime, 5338 publications have been published within this topic receiving 116760 citations.

Effects of interfacial heat transfer, surface tension and contact angle on the formation of plasma-sprayed droplets through simulation study

Abstract: A comprehensive numerical study of the effects of interfacial heat transfer, surface tension (1.8 N/m, 1.647 N/m, 1.35 N/m and temperature-dependent values) and contact angles (60°, 90° and 120°) on the droplet spreading behaviour in the formation of the plasma-sprayed splats was conducted. The evolution of splat morphologies with time was accurately captured using a volume of fluid (VOF) model in a 2-D computational domain. The results show that bubbles form at the time of impact and decrease the heat transfer efficiency at the contact points. During spreading, solidification occurs at the droplet edge before maximum spreading. The rapid growth of the underlying solidified layer induces fluid instabilities for the upper liquid layer, which triggers material jetting. The interfacial heat transfer is the key parameter influencing the droplet cooling process and the final splat morphology. Increasing the substrate preheating temperatures (from 27 °C to 300 °C) delays solidification but increases the potential of substrate melting. A low surface tension (1.35 N/m) readily promotes liquid projections, while the contact angle is of less importance in changing the surface morphologies.

Trajectory encounter volume as a diagnostic of mixing potential in fluid flows

Abstract: . Fluid parcels can exchange water properties when coming into contact with each other, leading to mixing. The trajectory encounter mass and a related simplified quantity, the encounter volume, are introduced as a measure of the mixing potential of a flow. The encounter volume quantifies the volume of fluid that passes close to a reference trajectory over a finite time interval. Regions characterized by a low encounter volume, such as the cores of coherent eddies, have a low mixing potential, whereas turbulent or chaotic regions characterized by a large encounter volume have a high mixing potential. The encounter volume diagnostic is used to characterize the mixing potential in three flows of increasing complexity: the Duffing oscillator, the Bickley jet and the altimetry-based velocity in the Gulf Stream extension region. An additional example is presented in which the encounter volume is combined with the u∗ approach of Pratt et al. (2016) to characterize the mixing potential for a specific tracer distribution in the Bickley jet flow. Analytical relationships are derived that connect the encounter volume to the shear and strain rates for linear shear and linear strain flows, respectively. It is shown that in both flows the encounter volume is proportional to time.

Computational Fluid Dynamics (CFD) Modeling of Bubble Dynamics in the Aluminum Smelting Process

Abstract: This paper presents a microscale modeling approach for investigation of bubble dynamics in the aluminum smelting process. The motion of a single bubble has been studied through a computational fluid dynamics (CFD) model facilitated with the volume-of-fluid (VOF) method to capture the bubble shapes. Using a two-dimensional geometry of part of a real cell as the testing bed, the motion of different sized bubbles has been simulated in an air–water system and a CO2–cryolite system. Comparisons between the two systems are conducted through the three periods of bubble motion: bubble sliding under the anode, bubble releasing at the anode edge, and bubble rising in the side channel. It was found that both systems show similar trends in bubble dynamics, such as an increase in the bubble sliding velocity as the bubble size increases and the appearance of a thick head at large bubble sizes. Quantitatively, there are differences between the two systems, evidenced in terms of the detailed bubble dynamics at each perio...

CFD Simulation of Wave Run-Up on a Semi-Submersible and Comparison With Experiment

Abstract: Use of CFD tools for industrial offshore applications is a common practice nowadays. So is the need for validation of such tools against experimental results. This paper presents one of the CFD tools, ComFLOW, which solves Navier-Stokes equations and employs an improved Volume of Fluid (iVOF) method to find temporary location of fluid’s free surface. The code is used to simulate flow around a semi-submersible offshore platform due to an incoming regular wave. In particular, wave run-up on the semi’s columns and under-deck fluid impact phenomena are investigated on high-accuracy computational grids with number of cells being in range of 10 millions. Results of numerical simulations are compared with experimental data and focus is on local fluid flow details in immediate vicinity of the platform. Wave run-up on the platform’s columns and fluid pressures at various locations, including under-deck impact, are reported and verified against the experiment for a range of incoming wave heights.Copyright © 2009 by ASME