# Stability Evaluation of a Simplified Reclaimer Using Fluid-Structure Interaction
## 3 Results  
In this paper, it is intended to investigate the influence of wind speed on the failure of a given reclaimer using CFD and MDB analyses. CFD results predict the velocity field and streamlines, as well as the pressures imposed by the wind and the resulting forces. MDB results predict the reclaimer displacements, vibration levels, and the acting and reacting forces. The structure may fall when the destabilizing moment is higher than the stabilizing moment. The FEM 2-131/13 standard [25] considers a safety factor of 1.5, which means that when the ratio of \(Em/Dm\) is greater than this, the structure may fall. The standard considers only velocities below 36 m/s. For a frontal area of 524 square meters and a mass of 491.4 tons, the velocity of 36 m/s results in a wind pressure of 777.6 Pa, a force of 407.8 kN, and a destabilizing moment of 3.4 MN.m. The stabilizing moment is 24 MN.m,  
Figure 5: Boundary conditions. Figure 6: Mesh refinement—YZ Plane. leading to a condition in which the reclaimer would not fall. According to the standard, the condition for failure would occur at a wind speed of 68 m/s. In this condition, the ratio of the destabilizing and stabilizing moments is still below 1.5. The velocity at which this ratio exceeds 1.5 is 83 m/s. For this reason, the model was simulated for wind speeds of 36, 68, and 84 m/s. To evaluate the behavior of the structure for higher velocities, wind speeds of 100 and 132 m/s were also simulated. In all simulations, the airflow was considered unsteady due to structural vibration modes. Numerical results showed differences related to the analytical model. It was observed that the wind deflection to the superior part provided a vertical force promoting stability. Although the analytical model indicated a critical velocity of about 68 m/s, the numerical results showed pressure variations and forces stabilizing the equipment for velocities until 132 m/s. These differences may be attributed to the detailed analysis performed in the numerical simulation. The analytical model considers a flat area of 524 square meters, while the numerical solution represents a more realistic geometry, resulting in a different velocity and pressure distribution. Figure 7 presents the velocity fields for wind speeds from 36 m/s to 132 m/s. The vorticity and recirculation zone formed after the equipment increased with the wind velocities, indicating a higher flow perturbation with higher velocities. The reclaimer displacements were more significant with higher wind velocities, causing more disturbance to the fluid. Although the velocity gradients increased with the wind velocity, the recirculation zone did not increase similarly, and the airflow velocities increased to a lesser extent than the free current velocity. The comparative analysis of the complex and simplified reclaimer models, based on Figure 8, sheds light on the distinctions between CFD (computational fluid dynamics) and FSI (fluid-structure interaction) simulations under the conditions tested. The complex model, with a mesh size of 50 to 60 million elements, was analyzed using only CFD and was subjected to a wind speed of 36 m/s. This model captures the flow details with higher granularity, which is evident in the intricate wind patterns and pressure distributions observed. However, the simulation's time constraint limits the analysis to initial transient phenomena. Figure 7: Lateral velocity field—XY Plane—simplified FSI model. On the other hand, the simplified model, with a mesh size between 1 and 2 million elements, employed an FSI approach, integrating the interaction between the fluid flow and the structural response of the reclaimer. This approach provides a more comprehensive understanding of the system's behavior by considering the structure's flexibility and the resultant deflections that may affect the flow patterns.