Abstracts:
The Boussinesq’s hypothesis is frequently used for the closure of many turbulence models mainly because of its stiffness and low computational cost. However, it does not always represent correctly the physical problem. In this paper, one of the considerations behind Boussinesq’s hypothesis is explored: the idea that the mean strain tensor and the anisotropic Reynolds stress tensor have the same principal directions. Actually, nothing is forcing that condition and it may not be true as will be shown experimentally for the case of a turbulent boundary layer flow. The experiments were done at the Boundary Layer Wind Tunnel of the Institute for Technological Research (IPT), in São Paulo, Brazil. It was observed that in the region where a log law is respected, the angle between the principal directions of the two tensors increases with the proximity of the wall. In the region far from the wall, the principal directions tend to match.
Reference:
MARTINS, Gabriel Borelli; RODRIGUEZ, Sara. Verificação experimental da hipótese de Boussinesq para escoamento de camada limite turbulenta. Revista IPT Tecnologia e Inovação, v.3, n.10, p.53-61, 2019.
Access to the article on the newspaper website:
http://revista.ipt.br/index.php/revistaIPT/article/view/81/87
The Boussinesq’s hypothesis is frequently used for the closure of many turbulence models mainly because of its stiffness and low computational cost. However, it does not always represent correctly the physical problem. In this paper, one of the considerations behind Boussinesq’s hypothesis is explored: the idea that the mean strain tensor and the anisotropic Reynolds stress tensor have the same principal directions. Actually, nothing is forcing that condition and it may not be true as will be shown experimentally for the case of a turbulent boundary layer flow. The experiments were done at the Boundary Layer Wind Tunnel of the Institute for Technological Research (IPT), in São Paulo, Brazil. It was observed that in the region where a log law is respected, the angle between the principal directions of the two tensors increases with the proximity of the wall. In the region far from the wall, the principal directions tend to match.
Reference:
MARTINS, Gabriel Borelli; RODRIGUEZ, Sara. Verificação experimental da hipótese de Boussinesq para escoamento de camada limite turbulenta. Revista IPT Tecnologia e Inovação, v.3, n.10, p.53-61, 2019.
Access to the article on the newspaper website:
http://revista.ipt.br/index.php/revistaIPT/article/view/81/87
