In this paper, we introduce an interactive coastal wave simulation and visualization software, called Celeris. Celeris is an open source software which needs minimum preparation to run on a Windows machine. The software solves the extended Boussinesq equations using a hybrid finite volume -finite difference method and supports moving shoreline boundaries. The simulation and visualization are performed on the GPU using Direct3D libraries, which enables the software to run faster than real-time. Celeris provides a first-of-its-kind interactive modeling platform for coastal wave applications and it supports simultaneous visualization with both photorealistic and colormapped rendering capabilities. We validate our software through comparison with three standard benchmarks for non-breaking and breaking waves. IntroductionResearch with the Boussinesq-type equations has led to transformative changes in coastal engineering simulation and practice over the last few decades (e.g. [1]) These equations are powerful for the study of nearshore dynamics, including both nonlinear and dispersive effects. While Boussinesq-type equations are capable of simulating relatively short-waves, they are computationally more expensive than their counterpart, non-linear shallow water (NLSW) equations. The computational effort needed for Boussinesq-type equations hinders real-time simulations using them, requiring parallel processing on dozens to hundreds of CPU cores to achieve [2]. The needed supercomputing facilities are neither easily accessible nor inexpensive, particularly for the types of often low-budget coastal and civil engineering projects for which they are applicable. While Graphics Processing Units (GPUs), are affordable alternatives to accelerate these numerical models, they are not often leveraged for Boussinesq equations, perhaps because these equations do not easily lend themselves to highly parallel numerical schemes, due to their embedded implicit methods and large numerical stencils.Finite volume method (FVM), shock-capturing, flux reconstruction, and limiters can make wave modeling solvers more robust; such approaches are now commonly found in NLSW models (e.g. [3]). However application of FVM to Boussinesq-type equations is not straightforward [4]. With FVM and the associated solution-smoothing schemes, robustness of the model becomes greater. This is of high relevance here, as our goal is to provide an interactive simulation environment, where the user can alter the water surface and the bathymetry while the model is running. This interactive environment also needs fast concurrent 3-D visualization. We choose a hybrid finite volume-finite difference scheme to solve the governing equations. This hybrid discretization enables the software to benefit from the robustness of FVM, while retaining the high accuracy of the Boussinesq-type model. To achieve high computational speed, we solve the equations using the GPU, providing faster than real-time simulation speed on an average user laptop. We call our open source software ...

Fluent software has been used to simulate flow over a circular spillway and results were compared with experimental data. As the flow over a circular spillway is turbulent and has a free surface, its characteristics are complex and often difficult to be predicted. This study assesses the performance of some turbulence models to predict the hydraulic condition of flow over circular spillways. The Volume of Fluid (VOF) method is applied to obtain the free surface in each case. Such cases include highly swirling flows, stress-driven secondary flows and flows over circular spillways. Finally it is concluded that the results of RSM, RNG k-, Realizable k-, SST k-ω turbulence models agree well with experimental data.

Historical maps contain detailed geographic information difficult to find elsewhere covering long-periods of time (e.g., 125 years for the historical topographic maps in the US). However, these maps typically exist as scanned images without searchable metadata. Existing approaches making historical maps searchable rely on tedious manual work (including crowd-sourcing) to generate the metadata (e.g., geolocations and keywords). Optical character recognition (OCR) software could alleviate the required manual work, but the recognition results are individual words instead of location phrases (e.g., "Black" and "Mountain" vs. "Black Mountain"). This paper presents an end-to-end approach to address the real-world problem of finding and indexing historical map images. This approach automatically processes historical map images to extract their text content and generates a set of metadata that is linked to large external geospatial knowledge bases. The linked metadata in the RDF (Resource Description Framework) format support complex queries for finding and indexing historical maps, such as retrieving all historical maps covering mountain peaks higher than 1,000 meters in California. We have implemented the approach in a system called mapKurator. We have evaluated mapKurator using historical maps from several sources with various map styles, scales, and coverage. Our results show significant improvement over the state-of-the-art methods. The code has been made publicly available as modules of the Kartta Labs project at https://github.com/kartta-labs/Project. CCS CONCEPTS • Applied computing → Document analysis; Graphics recognition and interpretation; • Information systems → Digital libraries and archives.

Tsunami‐induced coastal currents are spectacular examples of nonlinear and chaotic phenomena. Due to their long periods, tsunamis transport substantial energy into coastal waters, and as this energy interacts with the ubiquitous irregularity of bathymetry, shear and turbulent features appear. The oscillatory character of a tsunami wave train leads to flow reversals, which in principle can spawn persistent turbulent coherent structures (e.g., large vortices or “whirlpools”) that can dominate damage and transport potential. However, no quantitative measurements exist to provide physical insight into this kind of turbulent variability, and no motion recordings are available to help elucidate how these vortical structures evolve and terminate. We report our measurements of currents in Ventura Harbor, California, generated by the 2015 Chilean M8.3 earthquake. We measured surface velocities using GPS drifters and image sequences of surface tracers deployed at a channel bifurcation, as the event unfolded. From the maps of the flow field, we find that a tsunami with a near‐shore amplitude of 30 cm at 6 m depth produced unexpectedly large currents up to 1.5 m/s, which is a fourfold increase over what simple linear scaling would suggest. Coherent turbulent structures appear throughout the event, across a wide range of scales, often generating the greatest local currents.

The velocity field in a reservoir in the presence of surface vortices was experimentally studied. Experiments were performed with a horizontal intake and with a constant submerged depth and two different intake Froude numbers.The spline smoothing method was used to improve the graphical presentation of the measured data. Results are presented and compared in different horizontal sections in the reservoir. A downward conical flow over the intake axis and an upward one below the intake axis were observed in the reservoir. Finally, the prevailing domains of vertical and horizontal velocities were determined.