Mesoscale modeling of coastal low‐level jets: implications for offshore wind resource estimation

Detailed and reliable spatiotemporal characterizations of turbine hub height wind fields over coastal and offshore regions are becoming imperative for the global wind energy industry. Contemporary wind resource assessment frameworks incorporate diverse multiscale prognostic models (commonly known as mesoscale models) to dynamically downscale global‐scale atmospheric fields to regional‐scale (i.e., spatial and temporal resolutions of a few kilometers and a few minutes, respectively). These high‐resolution model solutions aim at depicting the expected wind behavior (e.g., wind shear, wind veering and topographically induced flow accelerations) at a particular location. Coastal and offshore regions considered viable for wind power production are also known to possess complex atmospheric flow phenomena (including, but not limited to, coastal low‐level jets (LLJs), internal boundary layers and land breeze–sea breeze circulations). Unfortunately, the capabilities of the new‐generation mesoscale models in realistically capturing these diverse flow phenomena are not well documented in the literature. To partially fill this knowledge gap, in this paper, we have evaluated the performance of the Weather Research and Forecasting model, a state‐of‐the‐art mesoscale model, in simulating a series of coastal LLJs. Using observational data sources we explore the importance of coastal LLJs for offshore wind resource estimation along with the capacity to which they can be numerically simulated. We observe model solutions to demonstrate strong sensitivities with respect to planetary boundary layer parameterization and initialization conditions. These sensitivities are found to be responsible for variability in AEP estimates by a factor of two. Copyright © 2013 John Wiley & Sons, Ltd.     

Model falsification diagnosis and sensor placement for leak detection in pressurized pipe networks

Pressurized pipe networks used for fresh-water distribution can take advantage of recent advances in sensing technologies and data-interpretation to evaluate their performance. In this paper, a leak-detection and a sensor placement methodology are proposed based on leak-scenario falsification. The approach includes modeling and measurement uncertainties during the leak detection process. The performance of the methodology proposed is tested on a full-scale water distribution network using simulated data. Findings indicate that when monitoring the flow velocity for 14 pipes over the entire network (295 pipes) leaks are circumscribed within a few potential locations. The case-study shows that a good detectability is expected for leaks of 50 L/min or more. A study of measurement configurations shows that smaller leak levels could also be detected if additional pipes are instrumented.     

Preliminary investigation of bioadvantaged polymers as sustainable alternatives to petroleum-derived polymers for asphalt modification

Due to recent volatility in the petroleum market, the possibility of using sustainable alternative materials as substitutes has gained great interest and viability. The purpose of this research is fourfold: to demonstrate how bioadvantaged polymers are produced using non-food soybean oil and showcase their economic and environmental value; to evaluate how they perform rheologically in asphalt against commonly used petroleum-derived polymers; to optimize the formulation of the bioadvantaged polymer for warm climate regions pavement applications based on the grading results, and to verify the modification effects of optimized bioadvantaged polymer by running performance grade tests. The study on economic and environmental implications demonstrated that poly(styrene-acrylated epoxidized soybean oil) (PS-PAESO) is more cost-effective, environmentally friendly, and safer to produce than styrene-butadiene (SB) polymer. The commercially produced petroleum-derived SB diblock polymer was used for comparison, while the laboratory produced bioadvantaged polymers were targeted at 1.25 MDa molecular weight of PS-PAESO diblock copolymers that consist of PAESO with various polystyrene (PS) molecular weights and contents. The effectiveness and rheological performance of the polymer modified asphalt binders were evaluated through binder investigations. Rheology test results indicated that the bioadvantaged polymers improved the stiffness, elasticity, and rutting resistance of the neat asphalt binder. Best-fit prediction models were developed through response surface modeling to optimize the PS-PAESO formulation in terms of PS content and molecular weight and the models were verified to be highly accurate based on the grading results. It was found that lower polystyrene content in PS-PAESO polymer could be beneficial in the improvement of critical high temperatures.     

Modeling Groups of Plausible Virtual Pedestrians

In a proposed methodology for modeling dynamic crowd scenarios, a video corpus informs the modeling process, after which the resultant animations undergo perception-based evaluation. The aim is to improve the crowd's visual plausibility rather than the simulation's correctness. A real-life crowd animation system demonstrates the methodology's practical application.     

Analysis of pressure profile and flow progression in the vacuum infusion process

New experimental set-ups are presented for measuring the pressure profile and fill-times in the Vacuum Infusion (VI) process. In these set-ups, the injection can either be from one of the mould faces (resulting in a rectilinear flow) or from a central port (resulting in a radial flow). From these measurements, the validity of previously reported analytical formulations is investigated. At the start of injection, the experimental results show a marked difference from analytical predictions. However, with flow progression, they change to match with analytical predictions. This phenomenon has not been observed previously and its analysis enhances the current understanding of the process physics, mainly the impact of compliance on the reinforcement thickness and flow progression.