URANS-Based Prediction of Vortex Induced Vibrations of Circular Cylinders

Abstract

Vortex induced vibrations (VIV) are highly nonlinear due to three different frequencies involved in the process; fluid force frequency, vortex shedding frequency and oscillation frequency. It is computationally complex to solve such a chaotic fluid flow but recent progress in numerical algorithms, turbulence models and computer capabilities have made it easier to approach the problem with a nonlinear approach. These developments have paved the way to approach the problem with the simple equation of motion of Newton's law and when coupled with URANS, which is a commonly used method in solving problems related to fluid flow, the highly nonlinear problem of vortex induced vibrations become solvable. The existing literature computationally can only handle flows for > 10,000 − 12,000 but the numerical methodology adopted in this study furthers this limitation. The numerical algorithm is first tried for a stationary cylinder and the boundary layer separation is investigated for higher . The generated results are found to be satisfactory to proceed solving for VIV at high . The solution strategy is tested in a wide range of Reynolds number with different springs and damping coefficients. Satisfactory agreement is found with the experiments for a cylinder in VIV. The shortcomings of the computational work and why these limitations arise are tried to be explained using the experimental results and the existing mathematical models.

A Numerical Study of the Flow Interference between Two Circular Cylinders in Tandem by Scale-Adaptive Simulation Model

“…9(a)), which would explain the reduction in the drag coefficient for the upstream cylinder. This conclusion is also confirmed recently by Rajani et al (2012) and Dobrucali and Kinaci (2017), who conducted URANS simulations of a circular cylinder in freestream using SST turbulence model. An interesting observation to note is that a similar trend is observed when compared with the experimental data, i.e., a slow decrease in CD1 with increasing L/D until a minimum and then jumps to higher values close to the value for a single cylinder.…”

Two-dimensional simulations of vortex-induced vibration of a circular cylinder

“…The physical mechanism behind the simulation of vortex-induced vibration was well explained by Khalak and Williamson 6 and Dobrucali and Kinaci 36 and hence, not given here in detail. In the present section, the results of vortex-induced vibration for the Reynolds number 2221 4 Re 4 6661 are presented.…”

Uncertainty Analysis of Experiments of Vortex-Induced Vibrations for Circular Cylinders

“…Computational fluid dynamics based methods are relatively new in this field. Wu et al (2014), Kinaci (2016) and Dobrucali and Kinaci (2017) performed numerical analysis study to evaluate the flow induced motion of circular cylinder for different conditions, using URANS model and compared them with VIV experiments. Kinaci et al (2016b) assessed the turbulence effect on the flow induced motion of a circular cylinder, comparing numerical and experimental results.…”