TY - GEN A1 - Neumeister, Roberta Fatima A1 - Reichel, Christoph A1 - Prisco Petry, Adriane A1 - Viçosa Möller, Sergio T1 - NUMERICAL ANALYSIS OF FLOW INTERACTIONS WITHIN A BANK OF TUBES WITH CLOSE SPACE RATIO T2 - FIV-2024-0052, FIV2024; FSI & FIV + N 10th Symposium on Fluid-Structure Interactions, Flow-sound Interactions, Flow-Induced Vibration & Noise N2 - The flow within a tube bank is characterized by multiple concurrent interaction mechanisms, contributing to a complex response. To gain a better understanding of these mechanisms, it can be helpful to simplify the problem by focusing on fixed rows to apply the free-to-vibrate approach later. This study conducts a numerical analysis of the fundamental characteristics of crossflow in five rows of stationary cylinders. Our goal is to establish a connection between the variations in velocity fields, the forces acting on the cylinders, and the expected vibration response. Simulations of cylinder rows were executed within a domain featuring a cross-section of 0.193 m x 0.146 m and a length of 0.8 m. The cylinders, with an external diameter of 25 mm, were placed with a longitudinal and transverse spatial ratio of 1.26. The governing equations, including continuity and Navier-Stokes equations, were solved using Large Eddy Simulation with the Smagorinski-Lilly subgrid model, employing dynamic stress modeling within Ansys Fluent 19. The Reynolds number was set at 8.4 x 10^3, based on the gap flow velocity and the diameter of a single cylinder. The results from the transient field indicate interactions between the gap flow and the cylinders following literature experimental visualizations and numerical simulations. Variations in velocity within the gaps between the cylinders highlight the dynamic redistribution of flow. This flow pattern significantly influences the forces acting on the cylinders, demonstrating an increase in force coefficients at specific cylinder positions. The sudden increase in the lift force in one of the cylinders can be the main factor related to the fluid-elastic instability occurrence. KW - numerical analysis, crossflow, tube bank, velocity fields. Y1 - 2024 ER - TY - CHAP A1 - Neumeister, Roberta Fatima A1 - Reichel, Christoph A1 - Prisco Petry, Adriane A1 - Möller, Sergio Viçosa T1 - Numerical analysis of crossflow over one and two rows of cylinders T2 - Proceedings of the 27th International Congress of Mechanical Engineering N2 - The flow inside a bank of tubes is complex and presents several interaction mechanisms acting at the same time in different positions of the equipment. Simplifying the structures to two cylinders or a few rows can be a way to understand part of the mechanisms and then extrapolate them to a bank of tubes. The flow over a single row in closed space presents wide and narrow wakes, similar to the structure observed in two cylinders side by side, these structures interacting with a second row show a significant change in the incoming flow parameters. The present study aims to show a numerical analysis of the main characteristics of the crossflow in one and two rows of fixed cylinders and to relate the changes in the pressure fields and forces in the cylinders to the expected vibration response. Simulations of rows of cylinders were performed in a domain with a cross-section of 0.193 x 0.05 m and a length of 0.8 m. Five and ten cylinders with an external diameter of 25 mm were applied. The longitudinal and transverse spatial ratio is 1.26 and all cylinders were fixed. The continuity and Navier-Stokes equations were solved using the Large Eddy Simulation with the Smagorinski-Lilly subgrid model with dynamic stress in Ansys Fluent 19. The Reynolds number is 5 x 10^4, based on the gap flow velocity and the diameter of a single cylinder. The transient analysis is performed with a time step of 1 x10^-5 s and the 10^-6 convergence criterion is used for all monitored variables. Preliminary results show wake asymmetry after the first and second rows of cylinders. There is an asymmetry between the velocity in the gaps between the cylinders indicating a redistribution of the flow, increasing and decreasing the velocity in the gaps between the cylinders. This velocity and pressure distribution influences the forces along the cylinders showing an increase in forces coefficients at some cylinder positions. The non-homogeneous distribution of velocity in the gaps is an important factor in determining the vibrational response, as the models use this information as an input parameter to determine the instability limits. KW - numerical analysis, crossflow, row of cylinders, flow-induced vibration Y1 - 2023 U6 - https://doi.org/10.26678/ABCM.COBEM2023.COB2023-0404 PB - ABCM ER -