| Journal: | Journal of the Brazilian Society of Mechanical Sciences and Engineering |
| Database: | PERIÓDICA |
| System number: | 000312366 |
| ISSN: | 1678-5878 |
| Authors: | Martinez, Denise Maria V1 Schettini, Edith Beatriz C2 Silvestrini, Jorge Hugo3 |
| Institutions: | 1Fundacao Universidade Federal do Rio Grande, Departamento de Matematica, Rio Grande, Rio Grande do Sul. Brasil 2Universidade Federal do Rio Grande do Sul, Instituto de Pesquisas Hidraulicas, Rio Grande, Rio Grande do Sul. Brasil 3Pontificia Universidade Catolica do Rio Grande do Sul, Departamento de Engenharia Mecanica, Rio Grande, Rio Grande do Sul. Brasil |
| Year: | 2006 |
| Season: | Abr-Jun |
| Volumen: | 28 |
| Number: | 2 |
| Pages: | 242-252 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental |
| English abstract | The transition to turbulence in a stably stratified flow is a problem of considerable interest in fluid dynamics with applications in both geophysical sciences and engineering. This transition is controlled by competition between the vertical shear of the base flow and the buoyancy forces due to the density stratification. The present work investigates numerically the effect of stable stratification on the development of a Kelvin-Helmholtz (KH) instability and the formation of streamwise vortices, which are developed after the saturation of the primary billows of KH. The Direct Numerical Simulation (DNS) technique was used to solve the complete Navier-Stokes equations, in the Boussinesq approximation. Numerical tests were done with different Richardson numbers and forced initial conditions for velocity fluctuations. The results showed that high stratification inhibits the pairing process, reduces the buoyancy flux, weakens the vertical motions, decreases the thickness of the mixing layer and affects the formation of streamwise vortices. The three-dimensional results demonstrated that the streamwise vortices are clearly formed in non-stratified cases. In the stratified cases, on the other hand, the streamwise vortices are weakened, due to the streamwise density gradient, which decrease the levels of vorticity in the billows of KH, while increase in the braid zone |
| Disciplines: | Ingeniería, Geociencias |
| Keyword: | Ingeniería mecánica, Geofísica, Turbulencia, Estratificación, Estabilidad, Dinámica de fluidos |
| Keyword: | Engineering, Earth sciences, Mechanical engineering, Geophysics, Stability, Fluid dynamics, Turbulence, Stratification |
| Full text: | Texto completo (Ver PDF) |
