A numerical research with different turbulence models for shallow water equations was carried out. This was done in order to investigate which model has the ability to reproduce more accurately the wakes produced by the shock of the water hitting a submerged island inside a canal. The study of this phenomenon is important for the numerical methods application advancement in the simulation of free surface flows since these models involve a number of simplifications and assumptions that can have a significant impact on the numerical solutions quality and thus can not reproduce correctly the physical phenomenon. The numerical experiments were carried out on an experimental case under controlled conditions, consisting of a channel with a submerged conical island. The numerical scheme is based on the Eulerian-Lagrangian finite volume method with four turbulence models, three mixing lengths (ml), and one joining -on the horizontal axis with a mixing-length model (ml) on the vertical axis. The experimental results show that a -with ml turbulence model makes it possible to approach the experimental results in a more qualitative manner. We found that when using only a -model in the vertical and horizontal direction, the numerical results overestimate the experimental data. Additionally the computing time is reduced by simplifying the turbulence model.
This paper describes the development of a two-dimensional water quality model that solves hydrodynamic equations tied to transport equations with reactions mechanisms inherent in the processes. This enables us to perform an accurate assessment of the pollution in a coastal ecosystem. The model was developed with data drawn from the ecosystem found in Mexico’s southeast state of Tabasco. The coastal ecosystem consists of the interaction of El Yucateco lagoon with Chicozapote and Tonalá rivers that connect the lagoon with the Gulf of Mexico. The results of pollutants transport simulation in the coastal ecosystem are presented, focusing on toxic parameters for two hydrodynamic scenarios: wet and dry seasons. As it is of interest in the zone, the transport of four metals is studied: Cadmium, Chromium, Nickel, and Lead. In order to address these objectives, a self-posed mathematical problem is solved numerically, which is based on the measured data. The performed simulations show how to characterise metals transport with an acceptable accuracy, agreeing well with measured data in total concentrations in four control points along the water body. Although for the accurate implementation of the hydrodynamic-based water quality model herein presented boundary (geometry, tides, wind, etc.) and initial (concentrations measurements) conditions are required, it poses an excellent option when the distribution of solutes with high accuracy is required, easing environmental, economic, and social management of coastal ecosystems. It ought to be remarked that this constitutes a robust differential equation-based water quality model for the transport of heavy metals. Models with these characteristics are not common to be found elsewhere.
We develop a numerical model based on the mild-slope equation of water wave propagation over complexbathymetrys, taking into account the combined effects of refraction, diffraction and reflection due to protectionstructures. The numerical method was developed using a split proposed version of the mild-slope equation in ellipticalform and solved by an implicit method in a finite volume mesh, this technique easily allows the modeling of the wavetransformations caused by the protection structures in coastal waters, where industrial and other economic activitiestake place. Study cases controlled have been made and the results match very well with the reference solution. Thecapability and utility of the model for coastal areas are illustrated by its application to the breakwater of the LagunaVerde Nuclear Power Plant (LVNPP) and the protection structure of the Nautical Marine named “Los Ayala”.
In this work a fast computational particles tracer model is developed based on Particle-In-Cell method to estimate the sediment transport in the access zone of a river port area. To apply the particles tracer method, first it is necessary to calculate the hydrodynamic fields of the study zone to determine the velocity fields in the three directions. The particle transport is governed mainly by the velocity fields and the turbulent dispersion. The mechanisms of dispersion and resuspension of particles are based in stochastic models, which describes the movement through a probability function. The developed code was validated using two well known cases with a discrete transformation obtaining a max relative error around 4.8% in both cases. The simulations were carried out with 350,000 particles allowing us to determine under certain circumstances different hydrodynamic scenarios where the zones are susceptible to present erosion and siltation at the entrance of the port.
A numerical model based on the mild-slope equation of water wave propagation over complicated bathymetry, taking into account the combined effects of refraction, diffraction, and reflection due to breakwater, is presented. The numerical method was developed using a split proposed version of the mild-slope equation and solved by an implicit method in a finite volume grid; this technique easily allows model the wave effects caused by the breakwater building in coastal waters, where industrial and other economic activities take place. Controlled case studies have been made and the results match very well with the reference solution. The capability and utility of the model for real coastal areas are illustrated by application to the breakwater of the Laguna Verde Nuclear Power Plant (LVNPP).
Numerical estimation of Lyapunov exponents in non-linear dynamical systems results in a very high computational cost. This is due to the large-scale computational cost of several Runge-Kutta problems that need to be calculated. In this work we introduce a parallel implementation based on MPI (Message Passing Interface) for the calculation of the Lyapunov exponents for a multidimensional dynamical system, considering a weakly coupled algorithm. Since we work on an academic high-latency cluster interconnected with a gigabit switch, the design has to be oriented to reduce the number of messages required. With the design introduced in this work, the computing time is drastically reduced, and the obtained performance leads to close to optimal speed-up ratios. The implemented parallelisation allows us to carry out many experiments for the calculation of several Lyapunov exponents with a low-cost cluster. The numerical experiments showed a high scalability, which we showed with up to 68 cores.
In farming, sustainability together with food safety is one of the main objectives to be achieved. Aquaponics is a technique that combines aquatic animals, such as fish, with the hydroponic production of plants that function as biological filters. The proper functioning of the system is based on the dynamic balance of the elements that make it up. Several studies confer aquatic macrophytes such as L. minor, great attributes, highlighting their use for feeding different species. Unfortunately, there is very little information on the system management of macrophytes in aquaponics. To determine the appropriate management parameters for the cultivation of L. minor integrated into the production of Oreochromis niloticus, in aquaponics, three experiments were carried out to evaluate the effect of the hydraulic retention time (HRT), the planting density, plant dissemination and the balance of nutrients in the systems. The results show that the highest biomass production and plant growth are achieved with high flow rates and short HRTs. Planting density has a direct effect on the behaviour of the plant. Regarding the balanced budget, between 7% and 8% of the nutrients (input in dry matter, N and P) are retained by L. minor, keeping the water quality within adequate limits for tilapia production.
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