The flow induced by a rotationally oscillating and translating circular cylinder

Abstract

The temporal development of two-dimensional viscous incompressible flow induced by an impulsively started circular cylinder which performs time-dependent rotational oscillations about its axis and translates at right angles to this axis is investigated. The investigation is based on the solutions of the unsteady Navier-Stokes equations. A series expansion for small times is developed. The Navier-Stokes equations are also integrated by a spectral-finite difference method for moderate values of time for both moderate and high Reynolds numbers. The numerical method is checked with the results of the analytical solution. The effects of the Reynolds number and of the forcing Strouhal number S on the laminar asymmetric flow structure in the near-wake region are studied. The lift and drag coefficients are also extracted from numerical results. An interesting phenomenon has been observed both in the flow patterns and in the behaviour of drag coefficients for S = π/2 at Reynolds number R = 500 and is discussed. For comparison purposes the start-up flow is determined numerically at a low Reynolds number and is found to be in good agreement with previous experimental predictions.

Numerical Investigation of a Rotationally Oscillating Cylinder in Mean Flow

“…Similar work was carried out by Chou (1997). Recently, using a spectral-"nite di!erence method, the #ow induced by a rotationally oscillating and translating circular cylinder was investigated by Dennis et al (2000) at Re"500 in a range of f A / f "0)883}2)5, and Re"1000 at two values of f A / f "1)25 and 2)5. The normalised oscillating amplitude is "xed at 1.…”

Suppression of vortex shedding for flow around a circular cylinder using optimal control

“…This will determine the apparition of a 'lock-on' phenomenon. In the case of time harmonic rotary oscillations it was described experimentally by Tokumaru and Dimotakis [4] and numerically by Chou [9] and Dennis et al [7] who studied the e ects of the forcing frequency and amplitude on a cylinder wake. If the forcing frequency lies in the neighborhood of the natural Karman frequency the combined system of cylinder and wake will be locked in (and, according to He et al [26], this is the optimal value for the forcing frequency for the drag reduction).…”

“…Research on the problem of a ow past a cylindrical rotating body has been the subject of many experimental [2][3][4], and numerical investigations [5][6][7][8][9]. However, most of these results are primarily focused on the study of formation and development of vortices in a cylinder wake and they do not attempt to suppress vortex shedding.…”

Numerical simulation of flow around an orbiting cylinder at different ellipticity values

“…In general, relatively simple forcing methods on the cylinder have been employed, e.g., in-line or transverse oscillation, rotational oscillation or orbital oscillation. However, in contrast to the fairly large number of studies conducted on the in-line, transverse and rotational oscillation cases [see for example, transverse oscillation: Ö ngo¨ren and Rockwell (1988), Williamson and Roshko (1988), Anagnostopoulos (1989), Meneghini and Bearman (1995), Lu and Dalton (1996), Kocabiyik and Nguyen (1999), Blackburn and Henderson (1999), Kaiktsis et al (2004); in-line oscillation: Mureithi et al (2004), Rodriguez (2005, 2006), Al-Mdallal et al (2007); rotational oscillation: Tokumaru and Dimotakis (1991), Baek and Sung (2000), Dennis et al (2000), Poncet (2004), Al-Mdallal and Kocabiyik (2006)], there is relatively little research carried out for the orbital motion.…”