An experimental/numerical study of the turbulent boundary layer development along a surface with a sudden change in roughness



Título del documento: An experimental/numerical study of the turbulent boundary layer development along a surface with a sudden change in roughness
Revista: Journal of the Brazilian Society of Mechanical Sciences
Base de datos: PERIÓDICA
Número de sistema: 000312027
ISSN: 0100-7386
Autores: 1
Instituciones: 1Universidade Federal do Rio de Janeiro, Programa de Engenharia Mecanica, Rio de Janeiro. Brasil
Año:
Volumen: 22
Número: 1
Paginación: 93-104
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental
Resumen en inglés A theory for the description of turbulent boundary layer flows over surfaces with a sudden change in roughness is considered. The theory resorts to the concept of displacement in origin to specify a wall function boundary condition for a kappa-epsilon model. An approximate algebraic expression for the displacement in origin is obtained from the experimental data by using the chart method of Perry and Joubert(J.F.M., vol. 17, pp. 193-122, 1963). This expression is subsequently included in the near wall logarithmic velocity profile, which is then adopted as a boundary condition for a kappa-epsilon modelling of the external flow. The results are compared with the lower atmospheric observations made by Bradley(Q. J. Roy. Meteo. Soc., vol. 94, pp. 361-379, 1968) as well as with velocity profiles extracted from a set of wind tunnel experiments carried out by Avelino et al.( 7th ENCIT, 1998). The measurements are found to be in good agreement with the theoretical computations. The skin-friction coefficient was calculated according to the chart method of Perry and Joubert(J.F.M., vol. 17, pp. 193-122, 1963) and to a balance of the integral momentum equation. In particular, the growth of the internal boundary layer thickness obtained from the numerical simulation is compared with predictions of the experimental data calculated by two methods, the "knee" point method and the "merge" point method
Disciplinas: Física y astronomía
Palabras clave: Dinámica de fluidos,
Mecánica, elasticidad y reología,
Turbulencia,
Capa límite,
Superficies,
Rugosidad,
Flujo atmosférico,
Modelos matemáticos
Keyword: Physics and astronomy,
Fluid dynamics,
Mechanics, elasticity and rheology,
Turbulence,
Boundary layer,
Surfaces,
Roughness,
Atmospheric flow,
Mathematical models
Texto completo: Texto completo (Ver HTML)