Numerical analysis of the influence of the dimensions of the spires in an atmospheric boundary layer wind tunnel

Luiz Fernando Ribeiro Ledo¹; Júlio César Xavier Ribeiro¹; Sérgio de Morais Hanriot¹; Cristiana Brasil Maia¹

¹ Pontifícia Universidade Católica de Minas Gerais

doi:10.20906/CPS/COB-2015-2027

Resumo

Wind tunnels used to simulate external fluid flows usually present large dimensions for the complete development of the fluid flow and the consequent possibility to suitably represent the atmospheric boundary layer. Because of the difficulty to build and operate large wind tunnels, spires are used to accelerate the boundary layer development. Spires are cut and folded devices of triangular plates, positioned in the test section inlet. In this work, a numerical model was developed to analyze the influence of the thickness and the size of the spires in the behavior of the fluid flow. The dimensions of the wind tunnel used as reference are those of the Plint & Patners LDD Whokinghan Bershire England wind tunnel. It has a squared test section, with 460 mm of edge and 1200 mm of length. It also uses a channel that extends the test section 1200 mm, with an internal width of 410 mm. The main dimensions of the spires were varied: the thickness of the plate with spires that have been constructed, the width of the base of the reinforcement plate relative to the triangular base plate and the width of the base of the triangular plate. The commercial software ANSYS - CFX was used to simulate the steady state turbulent airflow inside the device. The development of the boundary layer and the velocity profile were evaluated in the test section, and it was observed a small influence of the spires dimensions on the development of the boundary layer and on the fluid flow behavior.

Palavras-chave: ANSYS CFX; CFD; ATMOSPHERIC BOUNDARY LAYER WIND TUNNEL; SPIRES