“…where ij is the Kronecker delta, 2 i and Li are velocity variance at each component and the Lagrangian time scale (Degrazia et al, 2000), respectively. With the coordinates and the mass of each particle, the concentration is computed (see below).…”
Section: The Lagrangian Stochastic Model Lambdamentioning
confidence: 99%
“…The turbulence parameterization follows Degrazia et al (2000), for computing the wind variance ( Table 1. Next, the reverse trajectories are calculated for 1000 particles per sensor.…”
“…where ij is the Kronecker delta, 2 i and Li are velocity variance at each component and the Lagrangian time scale (Degrazia et al, 2000), respectively. With the coordinates and the mass of each particle, the concentration is computed (see below).…”
Section: The Lagrangian Stochastic Model Lambdamentioning
confidence: 99%
“…The turbulence parameterization follows Degrazia et al (2000), for computing the wind variance ( Table 1. Next, the reverse trajectories are calculated for 1000 particles per sensor.…”
“…Baseado nos desenvolvimento mostrados nas seções anteriores, Degrazia e co-autores em 2000 [27] apresentaram um novo conjunto de parametrizações da turbulência para todas as condições de estabilidade (convectiva, estável e neutra) da CLP. Usando a teoria de Taylor e as propriedades espectrais observadas dos turbilhões que contém energia, os autores apresentam as expressões para coeficiente turbulento (K i ), para as escalas de comprimento e de tempo Lagrangianas ( i e T i , onde i = u, v, w).…”
Section: Parametrizações Para Todas As Condições De Estabilidadeunclassified
“…Desta forma, o espectro de velocidades turbulentas pode ser expresso por O primeiro termo da Eq. (3.4.29)é o espectro de velocidade turbulenta gerado pelo fluxo de calor da superfície para a atmosfera: condição convectiva (CLC) [27] e o segundo termo representa o espectro gerado pelo cisalhamento do vento, podendo ser aplicado para as condições estável (CLE) [31] e neutra (CLN) [31], detalhadas anteriormente.…”
Section: Parametrizações Para Todas As Condições De Estabilidadeunclassified
“…In Equation (10), the product C 0 ε is calculated in terms of the turbulent velocity variance σ 2 i and the Lagrangian decorrelation time scale τ L i Hinze (1986); Tennekes (1982), which are parametrised according to a scheme developed by Degrazia et al (Degrazia et al (2000)). These parametrisations are based on Taylor's statistical diffusion theory and the observed spectral properties.…”
In this review we discuss a stochastic turbulent wind profile based on the three-dimensional stochastic Langevin equation for Gram-Chalier probability density function and a known mean wind velocity. Its solution permits to simulate radioactive substances dispersion in a turbulent regime, which is of interest for nuclear reactor accident scenarios and their related emergency actions. We discuss the stochastic Langevin equation together with an analytical method for solving the three-dimensional and time dependent equation which is then applied to radioactive substance dispersion for a stochastic turbulence model. The solution is obtained using the Adomian Decomposition Method, which provides a direct scheme for solving the problem without the need for linearisation and any transformation. The results of the model are compared to case studies with measured data and further compared to procedures and predictions from other approaches.
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