Application of Lattice Boltzmann Method for Surface Runoff in Watershed

Derived from simplifications of the Saint-Venant equations, the kinematic wave model has the ability to describe the behavior of surface runoff in watersheds. This paper aims to obtain the numerical simulation of the flow routing in a natural watershed, by using lattice Boltzmann method. In the computational model, the surface of the basin will be represented by a V-shaped segmented in two lateral planes and one main channel. The simulation considers the effective precipitation flowing on the watershed per unit of width at the exit of each of the planes that represent the surface of the basin. The water flowing from the planes enters the main channel in the form of lateral contribution. Hydrograms of two rain events are obtained, which present the volume drained in the outlet corresponding to the whole basin in each event. Two equilibrium distribution functions were developed by Chapmann-Enskog expansion at time scales and model D1Q3, one suitable for flow on the basin surface and another for the main channel, in order to obtain the variables of interest in each case. The numerical results obtained were compared with the KINEROS2 hydrological model.Peer Reviewe

Simulation of the two-dimensional flow of the initiation channel of the Itaipu hydroelectric power plant by the lattice Boltzmann method

Este artigo analisa a capacidade do método do reticulado de Boltzmann (LBM) com múltiplos tempos de relaxamento (MRT) na simulação do escoamento em problemas práticos de engenharia. O estudo de caso abordado refere-se ao primeiro trecho do canal de iniciação, que faz parte do canal da piracema, localizado no Usina Hidrelétrica de Itaipu. O canal de iniciação possui obstáculos submersos distribuídos de uma margem até a outra, com o objetivo de reduzir a velocidade da água e permitir a ocorrência do ciclo da piracema. As equações governantes do escoamento são as equações de águas rasas, que serão resolvidas por meio do LBM-MRT. Utilizou-se condições de contorno adequadas para escoamento em canal, vazão e altura da água constante na entrada e saída, respectivamente. Devido às características do problema que pretende-se simular, incorporou-se ao código computacional uma técnica de simulação em grandes escalas (LES - Large Eddy Simulation) a qual permite obter resultados mais próximos do comportamento real do escoamento. Além disso, avalia-se a estabilidade da simulação em todos os pontos da malha para cada passo de tempo e, juntamente com a propriedade da consistência do LBM, obtém-se a convergência da solução. A simulação fornece a profundidade, velocidades nas direções {\textstyle x} e {\textstyle y} , e a magnitude da vorticidade da água.This paper analyzes the ability of the Lattice Boltzmann method (LBM) with multiple relaxation times (MRT) in the simulation of flow in practical engineering problems. The case study covered refers to the first section of the initiation channel, which is part of the piracema channel, located in the Itaipu Hydroelectric Power Plant. The initiation channel has submerged obstacles distributed from one margin to the other, in order to reduce water velocity and allow the piracema cycle to occur. The governing equations of flow are the shallow water equations, which will be solved through the LBM-MRT. The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity.Peer Reviewe

Two-dimensional numerical simulation of channel flow with submerged obstacles using the lattice Boltzmann method

Apresenta-se a simulação numérica bidimensional do escoamento de água em um canal retangular com chicanas submersas distribuídas alternadamente nas suas margens. As equações governantes do escoamento são as equações de águas rasas, que serão resolvidas por meio do método do reticulado de Boltzmann (LBM) com múltiplos tempos de relaxamento (MRT). Utilizou-se condições de contorno adequadas para escoamento em canal, vazão e altura da água constante na entrada e saída, respectivamente. Devido às características do problema que pretende-se simular, incorporou-se ao código computacional uma técnica de simulação em grandes escalas (LES - Large Eddy Simulation) a qual permite obter resultados mais próximos do comportamento real do escoamento. Além disso, avalia-se a estabilidade da simulação em todos os pontos da malha para cada passo de tempo e, juntamente com a propriedade da consistência do LBM, obtém-se a convergência da solução. A simulação fornece a profundidade, velocidades nas direções {\textstyle x} e {\textstyle y} , e a magnitude da vorticidade da água.A two-dimensional numerical simulation of the water flow in a rectangular channel with submerged obstacles distributed alternately along its banks is presented. The governing equations of flow are the shallow water equations, which will be solved by the Boltzmann lattice method (LBM) with multiple relaxation times (MRT). The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity.Peer Reviewe

High-order CE/SE scheme for dam-break flow simulation

Este artigo apresenta um novo esquema explícito para a solução das equações de águas rasas em uma e duas dimensões, desenvolvido a partir do método dos elementos de conservação e elementos de solução espaço-tempo, aqui abreviado por método CE/SE. As funções de base utilizadas são expansões de Taylor de segunda ordem no tempo e no espaço. Esse aumento na ordem das funções de aproximação produz o aumento no número de variáveis de marcha no tempo, por isso, além das variáveis fluxo e suas inclinações, também são incógnitas no presente esquema suas derivadas espaciais de segunda ordem. Um processo iterativo para o cálculo das derivadas de primeira e segunda ordem é formulado para problemas com choques e descontinuidades. Experimentos computacionais demonstram acurácia de terceira ordem. Os problemas de ruptura de barragem unidimensional e bidimensional considerados validam a acurácia e robustez do esquema.This paper presents a new explicit scheme for the solution of shallow water equations in one and two space dimensions, developed from the space-time conservation element and solution element (CE/SE) method. The basis functions used are second-order Taylor expansions in time and space. This increase in the order of the approximation functions produces an increase in the number of unknowns in the scheme, therefore, besides the flow variables and their slopes, their second-order partial derivatives are also unknown in the present scheme. An iterative process for the calculation of the first and second order derivatives is formulated for problems with shocks and discontinuities. Computational experiments demonstrate third-order accuracy. The one-dimensional and two-dimensional dam-break problems presented validate the accuracy and robustness of this scheme.Peer Reviewe

A case study of a winter heavy rainfall event over the Serra do Mar in Brazil

La "Serra do Mar" es una estrecha cadena montañosa costera, localizada en el sudeste de Brasil, que abriga importantes ciudades, puertos, industrias y vías de comunicación. Esta región resulta muy vulnerable a las avalanchas de lodo y piedras, debido a sus inclinadas laderas y a las frecuentes e intensas lluvias. En el presente trabajo se estudia un caso de ocurrencia de avalanchas durante el período de invierno, es decir durante la estación seca, que sorprendió a las autoridades de la Defensa Civil y provocó la muerte de varias personas. El objetivo de la investigación es indagar las causas que condujeron a las avalanchas, con el fin de apoyar la tarea de los pronosticadores y los organismos tomadores de decisiones. Las lluvias fueron de tipo estratiforme y estuvieron asociadas a la presencia de un frente frío relativamente intenso que permaneció en la región alrededor de 6 días. Ese sistema se tornó estacionario en la costa del Estado de San Pablo, mientras que el anticiclón post–frontal, inicialmente frío, fue adquiriendo paulatinamente características barotrópicas. Esa situación originó vientos persistentes del sur y sudeste en superficie, que eran ascendidos por la Serra do Mar. El pasaje de una vaguada de onda relativamente corta en los niveles altos de la atmósfera, si bien no fue la causa principal de las lluvias, contribuyó a incrementar la inestabilidad termodinámica y, por lo tanto, a aumentar la intensidad de las lluvias creando condiciones favorables para la ocurrencia de avalanchas. doi: https://doi.org/10.22201/igeof.00167169p.2011.50.1.12

Simulation of the two-dimensional flow of the initiation channel of the Itaipu hydroelectric power plant by the lattice Boltzmann method

This paper analyzes the ability of the Lattice Boltzmann method (LBM) with multiple relaxation times (MRT) in the simulation of flow in practical engineering problems. The case study covered refers to the first section of the initiation channel, which is part of the piracema channel, located in the Itaipu Hydroelectric Power Plant. The initiation channel has submerged obstacles distributed from one margin to the other, in order to reduce water velocity and allow the piracema cycle to occur. The governing equations of flow are the shallow water equations, which will be solved through the LBM-MRT. The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity

Two-dimensional numerical simulation of channel flow with submerged obstacles using the lattice Boltzmann method

A two-dimensional numerical simulation of the water flow in a rectangular channel with submerged obstacles distributed alternately along its banks is presented. The governing equations of flow are the shallow water equations, which will be solved by the Boltzmann lattice method (LBM) with multiple relaxation times (MRT). The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity

Development of Inhibitors of SAICAR Synthetase (PurC) from Mycobacterium abscessus Using a Fragment-Based Approach.

Mycobacterium abscessus (Mab) has emerged as a challenging threat to individuals with cystic fibrosis. Infections caused by this pathogen are often impossible to treat due to the intrinsic antibiotic resistance leading to lung malfunction and eventually death. Therefore, there is an urgent need to develop new drugs against novel targets in Mab to overcome drug resistance and subsequent treatment failure. In this study, SAICAR synthetase (PurC) from Mab was identified as a promising target for novel antibiotics. An in-house fragment library screen and a high-throughput X-ray crystallographic screen of diverse fragment libraries were explored to provide crucial starting points for fragment elaboration. A series of compounds developed from fragment growing and merging strategies, guided by crystallographic information and careful hit-to-lead optimization, have achieved potent nanomolar binding affinity against the enzyme. Some compounds also show a promising inhibitory effect against Mab and Mtb. This work utilizes a fragment-based design and demonstrates for the first time the potential to develop inhibitors against PurC from Mab

Analysis of the prevalence of different topographical characteristics of the residual ridge in mandibular free-end arches Análise da prevalência de diferentes características topográficas do rebordo residual em arcos mandibulares com extremidades livres

This study observed the prevalence of different types of residual ridge inclination in free-ends of mandibles and reported possible correlative factors that may affect resorption. For this purpose, periapical radiographs and individual data collected from a sample of 64 hemiarches were used. Two radiographs were taken of each free-end, and tracing was employed to determine the angles formed by the resorption configuration in the area of the 1st mandibular molar. The following conclusions were drawn: 1) the great majority of alveolar ridges were distally descending; 2) the average angle was wider for users of mandibular removable partial dentures; 3) the results obtained suggest that the type of opposing maxillary arch affects the inclination of mandibular ridges; 4) greater inclination was observed when the 2nd bicuspids of the mandible were the abutment teeth; 5) no significant correlation was established between age, sex and residual ridge resorption.<br>Esta pesquisa constatou a prevalência dos tipos de rebordos residuais no sentido ântero-posterior em extremidades livres inferiores, além de correlacionar alguns fatores que possam influenciar as suas reabsorções. Para isso, utilizamos radiografias periapicais e dados individuais colhidos na amostra de 64 hemiarcos; foram obtidas 2 radiografias de cada área de extremidade livre e, a partir de traçados, determinamos os ângulos formados pela reabsorção na altura do 1º molar inferior. Podemos constatar que: 1º) a grande maioria de inclinação encontrada foi de rebordos descendentes para distal; 2º) a média de angulação foi maior para usuários de prótese parcial removível inferior; 3º) os resultados sugeriram existir influência do tipo de arco antagônico superior na inclinação dos rebordos inferiores; 4º) observou-se aumento de inclinação quando os segundos pré-molares inferiores eram os dentes adjacentes ao espaço protético; e 5º) não foram encontradas correlações significantes entre idade, sexo e reabsorção do rebordo residual