Title: Bifurcation of laminar flow around an elliptic cylinder at incidence for low Reynolds numbers

Authors: Hyun Sik Yoon; Jingbiao Yin; Changyoung Choi; S. Balachandar; Man Yeong Ha

Addresses: Global Core Research Center for Ships and Offshore Plants, Pusan National University, Jang Jeon 2-Dong, Geum Jeong Gu, Busan 609-735, Republic of Korea ' School of Mechanical Engineering, Pusan National University, Jang Jeon 2-Dong, Geum Jeong Gu, Busan 609-735, Republic of Korea ' School of Mechanical Engineering, Pusan National University, Jang Jeon 2-Dong, Geum Jeong Gu, Busan 609-735, Republic of Korea ' Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA ' School of Mechanical Engineering, Pusan National University, Jang Jeon 2-Dong, Geum Jeong Gu, Busan 609-735, Republic of Korea

Abstract: In this study, the fluid flow around an elliptic cylinder inclined to the free-stream was investigated for Reynolds numbers ranging from 20 to 100. The direct-forcing/fictitious domain (DF/FD) method was used to simulate the flow around the elliptic cylinder whose aspect ratio was 0.2 at angles of incidence ranging from 0° to 90°. The resultant instantaneous flow fields and patterns were then compared with those available in existing literature, and it was found that they compared favourably. The transition from steady to unsteady flow was shown using a stability diagram. An increase in the angle of incidence contributed to a decrease in the critical Reynolds number at which the flow became unsteady. In general, as the angle of incidence increased, the value of the Strouhal number decreased for a given Reynolds number. We also constructed a bifurcation diagram in order to distinguish the existence of recirculation regions behind the elliptic cylinder. Various characteristics of flow, such as Strouhal number, stagnation point, and drag and lift coefficients as a function of the angle of incidence were investigated.

Keywords: elliptic cylinders; angle of incidence; stability diagrams; bifurcation diagrams; laminar flow; Reynolds numbers; fluid flow; simulation; recirculation regions; Strouhal number; stagnation point; drag coefficient; lift coefficient.

DOI: 10.1504/PCFD.2016.076235

Progress in Computational Fluid Dynamics, An International Journal, 2016 Vol.16 No.3, pp.163 - 178

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 13 Apr 2016 *

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