Laminar flow past a rotating circular cylinder

Abstract

The present study numerically investigates two-dimensional laminar flow past a circular cylinder rotating with a constant angular velocity, for the purpose of controlling vortex shedding and understanding the underlying flow mechanism. Numerical simulations are performed for flows with Re=60, 100, and 160 in the range of 0⩽α⩽2.5, where α is the circumferential speed at the cylinder surface normalized by the free-stream velocity. Results show that the rotation of a cylinder can suppress vortex shedding effectively. Vortex shedding exists at low rotational speeds and completely disappears at α>αL, where αL is the critical rotational speed which shows a logarithmic dependence on Re. The Strouhal number remains nearly constant regardless of α while vortex shedding exists. With increasing α, the mean lift increases linearly and the mean drag decreases, which differ significantly from those predicted by the potential flow theory. On the other hand, the amplitude of lift fluctuation stays nearly constant with increasing α (<αL), while that of drag fluctuation increases. Further studies from the instantaneous flow fields demonstrate again that the rotation of a cylinder makes a substantial effect on the flow pattern.

Numerical simulations of flows over a rotating circular cylinder using the immersed boundary method

“…It is important to mention that the two first values of the critical rotation are in agreement with the results obtained by Kang et al (1999) that have performed simulations for Reynolds numbers equal to 60, 100 and 160. Figure 11 shows the streamlines for flow past a rotating circular cylinder obtained in the present study for four different instants of time.…”

“…They obtained the velocity profiles, the skin friction coefficient, the stagnation and the separation points for different values of the specific rotation, which varied from 0 to 1.25. Kang et al (1999) presented a numerical study of two-dimensional laminar flow over a rotating circular cylinder by taking into account a constant angular velocity, with the aim of controlling the vortex shedding and better understanding the flow dynamic. The numerical simulations were performed for flows by taking into account three different values of Reynolds numbers: 60, 100 and 160 in the range of…”

Effect of Rotation Rates on the Laminar Flow and Heat Transfer Past a Circular Cylinder

“…They found the second unsteady flow mode in a very narrow range of (α L2 ≤ α ≤ α L3 ). Also, Kang et al (1999) found that drag and lift coefficients decrease with an increase in rotation rate. Badr and Dennis (1989) found a decrease in laminar forced convection heat transfer with increasing rotation rate for an isothermal cylinder for Re = 5,10,20,40 and 100 at α ≤ 4.…”

“…This computer program applies a control-volume method to integrate the equations of motion, constructing a set of discrete algebraic equations with conservative properties. In particular, the O-type grid modified structure similar to that adopted by Kang et al (1999) was created here. The unsteady, laminar, segregated solver was employed here to solve the incompressible flow on the collocated grid arrangement.…”

“…All the meshes, M1 to M5, have the same distribution of nodes close to the cylinder. Kang et al (1999), while Mittal & Kumar (2003) used a dimensionless time step of 0.0125. Since the segregated method selected from the solver is implicit, no dependency on the time step occured in terms of numerical stability.…”