A Two-Field Formulation for Surfactant Transport within the Algebraic Volume of Fluid Method

Surfactant transport plays an important role in many technical processes and industrial applications such as chemical reactors, microfluidics, printing and coating technology. High fidelity numerical simulations of two-phase flow phenomena reveal rich insights into the flow dynamics, heat, mass and species transport. In the present study, a two-field formulation for surfactant transport within the algebraic volume of fluid method is presented. The slight diffuse nature of representing the interface in the algebraic volume of fluid method is utilized to track the concentration of surfactant at the interface as a volumetric concentration. Transport of insoluble and soluble surfactants is investigated by tracking two different concentrations of the surfactant, one within the bulk of the liquid and the other one at the interface. These two transport equations are in turn coupled by source terms considering the ad-/desorption processes at a liquid-gas interface. Appropriate boundary conditions at a solid-fluid interface are formulated to ensure surfactant conservation, while also enabling to study the ad-/desorption processes at a solid-fluid interface. The developed numerical method is verified by comparing the numerical simulations with well-known analytical and numerical reference solutions. The presented numerical methodology offers a seamless integration of surfactant transport into the algebraic volume of fluid method, where the latter has many advantages such as volume conservation and an inherent ability of handling large interface deformations and topological changes

Prelude to a Saturday nighter

This thesis pertains to the forgotten women dramatists of the Harlem/New Negro Renaissance of the 1920\u27s and 1930\u27s. It is divided into two parts: Preface and one-act drama. The Preface addresses the problems and issues when researching these women, namely the fact that there is little research devoted solely to their contributions to the movement. Set in the home of Georgia Douglas Johnson in late summer of 1929. Johnson is one of the most prolific women dramatists of the Harlem/New Negro Renaissance, whose works expanded even into the Civil Rights Movement, the one-act drama consists of a meeting between Johnson and Zora Neale Hurston, who is most notable for her non-dramatic works, despite the fact that it was in drama that she first made her mark. The first scene, set in the parlor, attends to the issue of race and how each woman goes about addressing their own representation of how race affects the African American community. In the second scene, the women are in the kitchen and address the most pressing issue of gender relations within the African American community