Abstract. An important practical feature of simulating droplet migration computationally, using the lubrication approach coupled to a disjoining pressure term, is the need to specify the thickness, H * , of a thin energetically stable wetting layer, or precursor film, over the entire substrate. The necessity that H * be small in order to improve the accuracy of predicted droplet migration speeds, allied to the need for mesh resolution of the same order as H * near wetting lines, increases the computational demands significantly. To date no systematic investigation of these requirements on the quantitative agreement between prediction and experimental observation has been reported. Accordingly, this paper combines highly efficient Multigrid methods for solving the associated lubrication equations with a parallel computing framework, to explore the effect of H * and mesh resolution. The solutions generated are compared with recent experimentally determined migration speeds for droplet flows down an inclined plane.
SUMMARYWe consider the parallel application of an efficient solver developed for the accurate solution of a range of droplet spreading flows modelled as a coupled set of nonlinear lubrication equations. The underlying numerical scheme is based upon a second-order finite difference discretization in space and a secondorder, fully implicit, adaptive scheme in time. At each time step, this leads to the need to solve a large system of nonlinear algebraic equations, for which the full approximation storage multigrid algorithm is employed. The motion of the contact line between the three phases (liquid, air and the solid substrate) is based upon the assumption of a thin precursor film, with a corresponding disjoining pressure term in the governing equations. It is the inclusion of this precursor film in the model that motivates the need for a parallel solution method. This is because the thickness of such a film must be very small in order to yield realistic predictions, while the finite difference grid must be correspondingly fine in order to obtain accurate numerical solutions. Results are presented which demonstrate that the parallel implementation is sufficiently efficient and robust to allow reliable numerical solutions to be obtained for a level of mesh resolution that is an order of magnitude finer than is possible using a single processor.
This research paper presents the outcome of a research conducted to assess and determine the Validity and Reliability coefficient of Creative Thinking Skills for Conceptual Engineering Design Module administered to engineering undergraduates at a private institution of higher learning. The Creative Thinking Skills Module features few proposed creative thinking tools such as Brain Sketching, Mind Maps and Morphological Analysis. The validity consists of module content validity, and session and activity validity, evaluated by a group of five experts. The Cronbach Alpha value was determined through conducting a pilot study in a local private university where mechanical engineering undergraduate underwent the module workshop and activity. Questionnaires were given to respective experts and students respondents to measure the validity and reliability level of the module, sessions and activities.
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