Atmospheric flow measurements using the PIV and HWA techniques

Ano: 2010 | Volume: 2 | Número: 2

Autores: Luciana Bassi Marinho Pires, Suelen T. Roballo, Gilberto Fisch, Ana Cristina Avelar, Roberto da Mota Girardi, Ralf Gielow

Palavras-chave: alcantara space center, wind profile, turbulent intensity, vorticity, stream lines

Resumo Inglês:

Alcântara Space Center (ASC) is the Brazilian gate to the space where rockets of different sizes are launched. At ASC there is a relative topographical variation, coastal cliff, which modifies the atmospheric boundary layer characteristics and can cause interference for operations of rockets. In the present work, a simplified model (mock-up) was studied in a wind tunnel. A scale factor of 1:1000 was used and the atmospheric flow was measured using the hot wire anemometer (HWA) and particle image velocimetry (PIV) techniques. Using of HWA it was possible to calculate values of average wind speed and fluctuations in a set of points of the section of tests that representing the region of the ASC. Through these measures, other meteorological parameters that represent the atmospheric flow, such as the friction velocity (u*), the roughness length (z0) from the logarithmic profile and the alpha exponent (ɑ) of the power law were calculated. With the use of the PIV´s technique, the streamlines and the vorticity fields were obtained and it was noticed that the vorticity generated downwind of the coastal cliff has a strong turbulence (vorticities around 2000 sˉ¹). A rectangular building (simulating the mobile integration tower) was inserted at the mock-up and the downwind turbulence was similar to the one generated by the coastal cliff.