Publicado
Mean velocity and suspended sediment concentration profile model of turbulent shear flow with probability density function
Velocidad media y modelo de perfil de concentración de sedimentos suspendidos de flujo turbulentos de cizalla turbulento con funciones de densidad de probabilidad
DOI:
https://doi.org/10.15446/esrj.v21n3.65172Palabras clave:
Exponential probability density, Mean velocity profile, Concentration profile, River flow, Coastal current (en)densidad de probabilidad exponencial, perfil de velocidad media, perfil de concentración, corriente de río, corriente costera. (es)
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This work purposes a general mean velocity and a suspended sediment concentration (SSC) model to express distribution at every point of the cross section of turbulent shear flow by using a probability density function method. The probability density function method was used to describe the velocity and concentration profiles interacted on directly by fluid particles in the turbulent shear flow to solve turbulent flow and avoid different dynamical mechanics. The velocity profile model was obtained by solving for the profile integral with the product of the laminar velocity and probability density, through adopting an exponential probability density function to express probability distribution of velocity alteration of a fluid particle in turbulent shear flow. An SSC profile model was also created following a method similar to the above and based on the Schmidt diffusion equation. Different velocity and SSC profiles were created while changing the parameters of the models. The models were verified by comparing the calculated results with traditional models. It was shown that the probability density function model was superior to log-law in predicting stream-wise velocity profiles in coastal currents, and the probability density function SSC profile model was superior to the Rouse equation for predicting average SSC profiles in rivers and estuaries. Outlooks for precision investigation are stated at the end of this article.
Este trabajo propone un modelo de velocidad media general y un modelo de concentración de sedimentos suspendidos (CSS) para expresar la distribución en cada punto de la sección de cruce del flujo turbulento de cizalla mediante el uso de funciones de densidad de probabilidad (PDF).. El método de funciones de densidad de probabilidad se usó para describir los perfiles velocidad y concentración que interactuaron directamente con partículas fluidas en el flujo de desprendimiento turbulento para resolver el flujo turbulento y evitar diferentes mecánicas dinámicas. El modelo del perfil de velocidad se obtuvo resolviendo el perfil integral con el producto de la velocidad laminar y la densidad de probabilidad, mediante la adopción de una función de desidad exponencial para expresar la probabilidad de distribución de la velocidad de alteración de la partícula de un fluido en un flujo de desprendimiento turbulento. También se creó un modelo de perfil CSS siguiendo un método similar al anterior y basado en la ecuación de difusión Schmidt. Se crearon diferentes perfiles de velocidad y CSS durante el cambio de parámetros de los modelos. Los modelos se verificaron comparando los resultados calculados con los modelos tradicionales. Se demostró que el PDF era superior a la ley logarítmica en la predicción de los perfiles de velocidad en corrientes costeras, y que la probabilidad del modelo del perfil de función de densidad SSC fue superior a la ecuación Rouse para predecir perfiles SSC promedio en ríos y estuarios. Las perspectivas para la investigación de precisión se indican al final de este artículo.
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