Space-time discontinuous Galerkin finite element method with dynamic grid motion for inviscid compressible flows. Part I. General formulation

A new space-time discontinuous Galerkin finite element method for the solution of the Euler equations of gas dynamics in time-dependent flow domains is presented. The discontinuous Galerkin discretization results in an efficient element-wise conservative upwind finite element method, which is particularly well suited for local mesh refinement. The upwind scheme uses a formulation of the HLLC flux applicable to moving meshes and several formulations for the stabilization operator to ensure monotone solutions around discontinuities are investigated. The non-linear equations of the space-time discretization are solved using a multigrid accelerated pseudo-time integration technique with an optimized Runge-Kutta method. The linear stability of the pseudo-time integration method is investigated for the linear advection equation. The numerical scheme is demonstrated with simulations of the flow field in a shock tube, a channel with a bump, and an oscillating NACA 0012 airfoil. These simulations show that the accuracy of the numerical discretization is $O(h^{5/2})$ in space for smooth subsonic flows, both on structured and locally refined meshes, and that the space-time adaptation can significantly improve the accuracy and efficiency of the numerical method. \u

Space-time discontinuous Galerkin finite element method with dynamic grid motion for inviscid compressible flows. Part II. Efficient flux quadrature

A new and efficient quadrature rule for the flux integrals arising in the space-time discontinuous Galerkin discretization of the Euler equations in a moving and deforming space-time domain is presented and analyzed. The quadrature rule is a factor three more efficient than the commonly applied quadrature rule and does not affect the local truncation error and stability of the numerical scheme. The local truncation error of the resulting numerical discretization is determined and is shown to be the same as when product Gauss quadrature rules are used. Details of the approximation of the dissipation in the numerical flux are presented, which render the scheme consistent and stable. The method is succesfully applied to the simulation of a three-dimensional, transonic flow over a deforming wing. \u

THE VIEWS OF MERWELENE VANDER MER WE AND HER TEAM ABOUT THE FASHION PHOTOGRAPHY WORKING ENVIRONMENT

ThesisFashion is seen as a glamorous world full of beautiful people and exorbitant amounts of money. I t was decided to get a closer look at this world as seen through the eyes of those who participate. This study consists of two components. A practical component comprising studio and on location photographs and a theoretical component dealing with fashion worlUng environment. As South Africa is becoming a non-sexist society and women are part of the main business stream, it was decided to focus on the highly successful photographic icon of fashion photography, Merwelene van der Merwe. The main aim of the study was to research the interaction between the fashion photographer and the main participants in a fashion photograph, in order to get each individual's interpretation of what makes a successful fashion photograph and fashion photographer. This was achieved through a preliminary intervic'W with Merwelene van der Merwe to see if the aim of the study was feasible. As the f,rst interview was most successful, the decision was made to place more emphasis on Merwelene van der Merwe. Follow-up interviews and a week's stay with Merwelene resulted. Articles, two television interviews and all other available material was researched to get a more comprehensive picture. As Merwelene has a unique way of speaJUng, the author decided to give her interviews verbatim so that the reader can feel the "electricity" generated by Merwelene. The intervi~ws were done in Afrikaans, Merwelene's home language. In this dissertation, all questions are given in English and Afrikaans. All questions are preceded by a Q and all answers by an A. To get a more comprehensive picture, the following people who form part of Merwelene's team were interviewed: (1) Her assistants Doret, (2)her model Simone,(3) her hair and make-up artist Marilyn, (4) an art director of an advertising agency Sandy and (5) a client Mariette. The dissert.ation is devided into four chapters, the first chapter, Merwelene van der Merwe discusses her background and outlook on life. In chapter two, Merwelene discusses fashion photography as a success ful busin ess. Chapter three covers the team she works with and their yiews. The final chapter concentrates on Merwelene's work as a fas hion photographer. Here two divergent photographs are discussed

What matters most to patients? Participative provider care and staff courtesy

Although there is growing recognition of the importance of having satisfied patients, we know little about what aspects of care matter most to patients. The sources of patient satisfaction and how care delivery can influence them need more empirical study. The objective of this study was to identify which aspects of a patient’s experience of care are most important to patient satisfaction, and how dimensions of care relate to clinic size, economic performance, and employee job satisfaction. To explore our question, longitudinal survey data were obtained on patients and employees over two years (1996 and 1997). Relationships between patient satisfaction and the two most critical care experience dimensions, clinic size, economic performance, and job satisfaction were examined. As of result, six major dimensions of patients\u27 experience of care were identified: 1) participative provider care, 2) staff courtesy, 3) self-reported sickness, 4) waiting, 5) staff follow-up, and 6) medical explanations. The first two factors, participative provider care and staff courtesy, account for more than 37% of the total variance in patients’ experience of care. Patient satisfaction is negatively and significantly correlated with clinic size but not correlated with job satisfaction, physician productivity, or clinic profitability. The article concludes suggesting that the personal relationships of a patient with his/her doctor and clinic staff are the strongest predictors of patient satisfaction. Patient satisfaction was found to be unrelated to the employee job satisfaction, physician productivity, and clinic economic performance

Extension of the discontinuous Galerkin finite element method to viscous rotor flow simulations

Heavy vibratory loading of rotorcraft is relevant for many operational aspects of helicopters, such as the structural life span of (rotating) components, op- erational availability, the pilot’s comfort, and the ef- fectiveness of weapon targeting systems. A precise understanding of the source of these vibrational loads has important consequences in these application ar- eas. Moreover, in order to exploit the full poten- tial offered by new vibration reduction technologies, current analysis tools need to be improved with re- spect to the level of physical modeling of flow phe- nomena which contribute to the vibratory loads. In this paper, a computational fluid dynamics tool for rotorcraft simulations based on first-principles flow physics is extended to enable the simulation of vis- cous flows. Viscous effects play a significant role in the aerodynamics of helicopter rotors in high-speed flight. The new model is applied to three-dimensional vortex flow and laminar dynamic stall. The applica- tions clearly demonstrate the capability of the new model to perform on deforming and adaptive meshes. This capability is essential for rotor simulations to accomodate the blade motions and to enhance vor- tex resolution

An explicit multi-time-stepping algorithm for aerodynamic flows

An explicit multi-time-stepping algorithm with applications to aerodynamic flows is presented. In the algorithm, in different parts of the computational domain different time steps are taken, and the flow is synchronized at the so-called synchronization levels. The algorithm is validated for aerodynamic turbulent flows. For two-dimensional flows speedups in the order of five with respect to single time stepping are obtained.