Library Subscription: Guest
Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
December, 14-17, 2023, Bihar, India

Vortex Interactions in Turbulent Flow through 90-degree Bend Pipe: A Parametric Study

Get access (open in a dialog) DOI: 10.1615/IHMTC-2023.590
pages 359-365


A computational fluid flow investigation of a smooth 90-degree bend pipe is conducted to identify the vortex structures. This is performed using invariants of the complex conjugate eigenvalues of the velocity gradient tensor, in a mean turbulent flow field. Subsequently, the interaction and propagation of these vortices through the bend is investigated by analyzing the swirling strength and incipient turbulence characteristics of flow. Furthermore, effect of parameters such as Reynolds number and curvature ratio on vortex interactions is studied. The Reynolds number is taken in the range of 1000 to 0.1 million while the curvature ratio is taken within the range of 0.01 to 0.2. Simulations are performed by solving the Reynolds averaged Navier-Stoke's equations for a steady state incompressible flow, using the Reynolds stress model to close turbulence-related variables. A qualitative viewpoint shows the region of maximum swirling strength in the bend and its dissipation trail when curvature is changed. However, insignificant change is observed in vortex structures with change in Reynolds number. With increase in curvature swirling strength maxima shifts away from the bend inlet to the vortex arms. This occurs up to a certain curvature, beyond which it significantly dissipates. Moreover, in the spanwise direction, vortex structures are densely distributed in the inner bend section and are propagated to the center at bend exit. It is also found that the turbulent kinetic energy is less at the inner bend section, which shows shifting of perturbations to the outer section of the bend. The rate of dissipation is also observed to be significantly reduced. Additionally, the intensity of perturbations is found to be greater in a narrower bend. With this parametric study, we aim to provide a better representation of vortex structure identification and interactions in general.