Effects of Chamber Shape on Simulation of Tornado-like Flow in a Laboratory

摘要

Considering that it is difficult to capture the characteristics of the wind field during a tornado event, especially the wind field near ground, it is important to reproduce the tornado-like vortices in the laboratory tornado simulator to systematically study the violent tornadic wind field and its effect on civil engineering structures. The tornado simulator studied here follows the same mechanism to generate the tornado-like vortices as the one at Iowa State University (ISU). That is, the flow, driven by the fan, self-circulates inside the simulator, and angular momentum is introduced by the guide vanes set at an angle with respect to the radius. A high-fidelity numerical model of this tornado simulator is established by modeling all the major mechanical components of the tornado simulator in the simulation, including the chamber/duct, guide vanes, fan, and honeycomb section. In order to identify the optimal shape for the laboratory tornado simulator, three tornado simulators with different geometric shapes of chambers are simulated. For each tornado simulator, both overall and near-floor tornadic wind fields are extracted. The obtained results show that the curved chamber provides a more stable flow compared with the multi-sided chamber that is used in the tornado simulator of ISU. The developed numerical model here helps gain more physical insights into tornado simulators, and impels the design optimization of this type of laboratory tornado simulator so that controllable tornado-like vortices can be better understood.