TY - JOUR
T1 - Forced streamwise oscillations of a circular cylinder
T2 - Locked-on modes and resulting fluid forces
AU - Al-Mdallal, Q. M.
AU - Lawrence, K. P.
AU - Kocabiyik, S.
N1 - Funding Information:
The financial support for this research is provided by the Natural Sciences and Engineering Research Council of Canada. Preliminary results of this research are reported at various conferences; see, e.g., Lawrence et al. (2003) , Al-Mdallal et al. (2003) .
PY - 2007/7
Y1 - 2007/7
N2 - A computational study of laminar, incompressible flow past a cylinder oscillating in the streamwise direction is performed using the two-dimensional unsteady Navier-Stokes equations in nonprimitive variables. The method of solution is based on a conjugating Fourier spectral analysis with finite-difference approximations. The numerical simulations are conducted at a fixed Reynolds number, R = 200, and at displacement amplitude-to-cylinder diameter of A = 0.1 and 0.3. Results show the existence of symmetric/asymmetric modes of vortex formation in the cylinder wake at different values of unsteady loading on the cylinder, which is characterized by the ratio of oscillation frequency, f, to Kármán vortex-shedding frequency, f0. For this paper, the frequency ratio is chosen from f / f0 = 0.5 to 3, where switching from asymmetric to symmetric vortex shedding is observed. The relation between these vortex-shedding modes and fluid forces on the cylinder surface is discussed. An analysis of the locked-on modes via Lissajous patterns of unsteady lift coefficient is also included. Previously computed and observed flow fields as well as fluid forces are compared to current numerical results and agreement is found to be excellent.
AB - A computational study of laminar, incompressible flow past a cylinder oscillating in the streamwise direction is performed using the two-dimensional unsteady Navier-Stokes equations in nonprimitive variables. The method of solution is based on a conjugating Fourier spectral analysis with finite-difference approximations. The numerical simulations are conducted at a fixed Reynolds number, R = 200, and at displacement amplitude-to-cylinder diameter of A = 0.1 and 0.3. Results show the existence of symmetric/asymmetric modes of vortex formation in the cylinder wake at different values of unsteady loading on the cylinder, which is characterized by the ratio of oscillation frequency, f, to Kármán vortex-shedding frequency, f0. For this paper, the frequency ratio is chosen from f / f0 = 0.5 to 3, where switching from asymmetric to symmetric vortex shedding is observed. The relation between these vortex-shedding modes and fluid forces on the cylinder surface is discussed. An analysis of the locked-on modes via Lissajous patterns of unsteady lift coefficient is also included. Previously computed and observed flow fields as well as fluid forces are compared to current numerical results and agreement is found to be excellent.
KW - Fluid forces
KW - Forced streamwise oscillation
KW - Incompressible
KW - Lock-on
KW - Unsteady
KW - Viscous
KW - Vortex formation
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U2 - 10.1016/j.jfluidstructs.2006.11.001
DO - 10.1016/j.jfluidstructs.2006.11.001
M3 - Article
AN - SCOPUS:34248192834
SN - 0889-9746
VL - 23
SP - 681
EP - 701
JO - Journal of Fluids and Structures
JF - Journal of Fluids and Structures
IS - 5
ER -