The accurate modeling of the landslide‐generated tsunami characteristics in the so‐called near‐field is crucial for many practical applications. In this paper, we present a new full‐3‐D numerical method for modeling tsunamis generated by rigid and impermeable landslides in OpenFOAM® based on the overset mesh technique. The approach has been successfully validated through the numerical reproduction of past experiments for landslide‐generated tsunamis triggered by a rigid and impermeable wedge at a sloping coast. The method has been applied to perform a detailed numerical study of the near‐field wave features induced by submerged landslides. A parametric analysis has been carried out to explore the importance of the landslide's initial acceleration, directly related to the landslide‐triggering mechanisms, on the tsunami generation process and on the related wave properties. Near‐field analysis of the numerical results confirms that the influence of the initial acceleration on the tsunami wave properties is significant, affecting wave height, wave period, and wave celerity. Furthermore, it is found that the tsunami generation mechanism experiences a saturation effect for increasing landslide's initial acceleration, confirming and extending previous studies. Moreover, the resulting extended database, composed of previous experimental data and new numerical ones, spanning a wider range of governing parameters, has been represented in the form of a “nondimensional wavemaker curve,” and a new relationship for predicting the wave properties in the near‐field as a function of the Hammack number is proposed.

AnoxAn is a novel multi-environment reactor for biological nutrient removal (BNR) from wastewater. Although its biological efficacy has been demonstrated on a pilot scale, hydrodynamics is observed to significantly affect the performance of AnoxAn. To study its complex hydraulic behaviour, a model based on Computational Fluid Dynamics 3D (CFD) is constructed using the OpenFOAM® open source toolbox and validated by experimental tests of Residence Time Distribution (RTD). Reactor elements represent a key factor in the modelling process. In this sense, the impeller of the anoxic zone is modelled as a flat disk, and the baffle after the anoxic zone as a porous media. According to CFD model simulations, stagnant, short-circuit zones and mixing quality are established and quantified. Finally, the influence on the hydrodynamics of reactor elements is also evaluated. The results of this detailed hydrodynamic analysis will form the basis for the design and optimization of scalable AnoxAn configurations.

Over the last years Navier-Stokes numerical models have been developed to accurately simulate wave interaction with all kinds of coastal structures, focusing on both functionality and stability of coastal structures. Although several models have been used to simulate wave interaction with coastal structures in two dimensions (2DV) there are a vast number of three-dimensional effects that need to be investigated in order to improve the design. In this paper a new model called IH-FOAM has been applied to study a vertical breakwater at prototype scale. As a first attempt of validation, the model has been used to simulate a regular wave train generated with a relative angle with the breakwater inducing three-dimensional wave patterns not only seaward the structure due to reflection but also generating an overtopping discharge variation along the breakwater trunk. Pressure laws and overtopping discharge at three different cross-sections along the structure have been studied. The pressure laws have been compared with classical Goda's formulation. Although, the numerical model predictions are in accordance with Goda's calculations, a clear three-dimensional variability of wave-induced pressure has been observed. Moreover, an additional study has been performed calculating pressure laws on the side-wall at the breakwater head. Large three-dimensional effects are detected from the simulations due to the flow separation at that area. Overtopping model predictions have been compared with Overtopping Manual calculations showing very close values along the trunk. However, lower overtopping discharge values are observed at the breakwater head. This paper is a preliminary work to show the range of applicability of a three-dimensional Navier-Stokes model to study wave interaction with a vertical breakwater under the action of an oblique wave train.

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