The Effects of Turbulent Fluctuations on Nonlinear von Kármán Vortex Shedding


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Ateş K., Bayındır C.

ICAME 2021, Balıkesir, Turkey, 1 - 03 September 2021, no.31, pp.1-5

  • Publication Type: Conference Paper / Full Text
  • City: Balıkesir
  • Country: Turkey
  • Page Numbers: pp.1-5

Abstract

Flows around bluff bodies generate wakes and vortices downstream of flow. This phenomenon is known as vortex shedding and such vortices are generally named as von Kármán vortices after Theodore von Kármán. Although such a phenomenon is introduced to the scientific literature by the study of fluid flows, it is also observed in other fields such as Bose-Einstein condensation. Due to the complexity of the governing equations and involved complex geometries, such phenomena are generally studied numerically using different software and various turbulent modeling techniques. One of the other commonly utilized models for the study of nonlinear vortex shedding is the complex Ginzburg-Landau (GL) equation [1-4]. This dynamic equation is an equation in the nonlinear Schrödinger class and also appears in various other branches of science. In this paper, we investigate the effects of turbulent fluctuations on the vortex shedding in the frame of the GL equation. With this aim, we solve the GL equation using a spectral scheme with a 4th order Runge-Kutta time integrator. For the spectral solution, efficient FFT routines are employed. We analyze the possible modulation instabilities causes by turbulent fluctuations, their effects on the regular stable vortices, and possible rogue vortex formation [5-6]. We also study the dynamics and statistics of such vortices under the effect of turbulent fluctuations. Our findings can be used for controlling, mitigating, or resonating the vortices and wake for many different engineering purposes including but are not limited to structural safety and serviceability considerations, noise reduction, energy harvesting, just to name a few.