Interaction between atmospheric flows and obstacles: Experiments in a rotating channel
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We performed an experimental study using scale models in a hydrodynamic rotating channel, concerning the interactions between fluid flows and obstacles of different shapes. The study was meant to analyze the characteristics of the wakes observed on the lee side of quasi-bidimensional obstacles, in a neutral atmosphere.
The obstacles were half-cylinders (with aspect ratio 0.87), placed transversally on the channel bottom and totally submerged in the fluid. We call them “quasi-bidimensional” since their width was a little smaller than the channel width, thus allowing the flow to partially go round their edges.
The simulations were performed in the rotating hydraulic channel of ICG-CNR in Turin, and included various conditions of rotation period and flow speed. An interesting behaviour of the wakes was found on the lee side of subsynoptic-scale obstacles, modelled in conditions of Reynolds-Rossby similitude. More precisely, if a given threshold of flow velocity is exceeded, wake size is constant and is fully determined by the height of the obstacle.
KeywordsAtmosphere Experimental Study Aspect Ratio Flow Velocity Fluid Flow
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- Alessio, S., Briatore, L., Ferrero, E., Longhetto, A., Giraud, C., and Morra, O.: 1989, ‘Experimental Results on Atmospheric Dynamical and Thermal Structures Modeled in a Rotating Hydraulic Channel’, Nuovo Cimento 12C, 427–438.Google Scholar
- Britter, R. E., Hunt, J. C. R., and Richards, K. J.: 1981, ‘Air Flow over a Two-dimensional Hill: Studies of Velocity Speed-Up, Roughness Effects and Turbulence’, Quart. J. R. Meteorol. Soc. 107, 91–110.Google Scholar
- Wippermann, F. and Yordanov, D.: 1972, ‘A Note on the Rossby Similarity for Flows of Barotropic Planetary Boundary Layers’, Beitrage zur Physik der Atmosphäre 45, 66–71.Google Scholar