This work contributes to the study of nuclear plant thermal discharges in coastal areas by using a numerical model which solves the Navier-Stokes-Reynolds equations for shallow waters and the energy equation for computing temperature variations. The numerical model takes into account the heat flux given in the upper layer, where the free surface and the atmosphere interact. In this study, the thermal plume dispersion from the nuclear power plant Laguna Verde, Veracruz, Mexico, is analyzed. Bathymetry, oceanographic, meteorological, hydrologic and plant operating data are used to run numerical simulations. The results are compared against observed data showing good agreement. The Nash-Suffle's criterion is also applied to verify the quality of the numerical solution obtaining suitable results
1 January 2017 in Mathematical Problems in Engineering
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.
Increased temperature due to global climate change is increasing the magnitude and frequency of extreme winds making billboard structures more vulnerable. This paper proposes a methodology to determine the structural safety of flexible outdoor single-post billboards. A CFD model of a flexible single-post billboard was performed as an example. Resultant wind forces were obtained for the previous model using different wind speeds. A mechanical numerical model of the billboard was realized, and this was subjected to the resultant wind forces. Internal forces for the most vulnerable places of the billboard were obtained for all different adopted wind speeds. Next, a reliability analysis of the billboard was performed considering several values for the bias factor and coefficient of variation for the internal forces caused by wind. Safety levels determined from the reliability analysis indicate that a billboard designed with a nominal wind speed of 180 km/h cannot achieve the target probability index of 3.2 for wind speed higher or equal to 200 km/h for any of the adopted probabilistic parameters. Significant differences in the found safety levels for the evaluated probability parameters indicate that billboard structures could undergo safety values below the target one with changes in the case where wind characteristics endanger this type of structure.
1 January 2010 in Modelling and Simulation in Engineering
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).
18 February 2023 in Modelling and Simulation in Engineering
The development and construction of highway infrastructure are essential in developing countries, whereas its layout and construction sometimes interact with the coastal environment. One problem to attend to is that the outline and geometry designs impact as little as possible on the hydrodynamic circulation of coastal bodies in order to alter the associated ecosystem as little as possible. The study area is located in the north of Colombia, and is made up of a continental coastal zone (Mallorquín Lagoon) and a marine zone (Caribbean Sea), in which a highway is projected that provides communication between two locations. This study presents the application of a numerical model previously developed and modified by the Berkhoff equation, which is developed in a finite difference scheme and has been validated and applied in different works in coastal and fluvial shallow water areas. The application of the model was carried out in a hydrodynamic circulation research project for a one-way highway through a coastal lagoon, where the knowledge of the magnitude of the incident wave height in the structure of the road body is necessary for the design, protection elements, and road geometry. Two numerical simulation scenarios were carried out, specifying normal conditions and extraordinary wave conditions in the month of November with a simulation time of 15 days, obtaining the velocity field associated with coastal currents, waves, and wave modification phenomena, such as refraction, diffraction, and reflection, which provide the height of the incident wave on the highway and the recirculation patterns in the coastal lagoon to identify alterations in the ecosystem. The results of the wave height in each scenario and the velocity field provide values to be used in the design, type of armor, and dimensions of the protection works required for the proper functioning of the road structure.
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.