Proceedings of Conference on Modelling Fluid Flow (CMFF'18)
Forrásdokumentum szerzői:
J Vad,
Év:
2018
Kiadó:
CFD.HU Kft.
Megjelenési hely:
Budapest
Az adatrekord státusza:
feldolgozás alatt
Megjegyzés/összefoglaló leírás:
Flow around a freely vibrating circular cylinder in two-
degrees-of-freedom is investigated at low Reynolds numbers
using two-dimensional numerical simulation. Systematic
computations are carried out to investigate the effect of
cylinder’s natural frequency fN on the oscillation amplitudes
and aerodynamic force coefficients. The mass ratio and the
structural damping coefficient values are fixed at m*=
10 and
ζ=
0, respectively.
In addition to the typical distorted figure-eight motion, a
raindrop-shaped path is also found whose range widens with
increasing fN. Within this range the streamwise cylinder
oscillation amplitude reaches higher values compared to
figure-eight motions and the curves shift upwards with
increasing fN. Sudden switches in the vortex structure occur
near the upper boundaries separating the raindrop-shaped and
distorted figure-eight motion domains. The root-mean-square
(rms) values of lift plotted against U*St0 shift upwards in
the raindrop-shaped motion range and downwards in the figure-
eight motion range, while the rms of drag shifts to higher
values in both regimes with increasing fN. The time-mean of
lift coefficient jumps abruptly between two solutions. Using
pre- and post-jump analysis it is shown that these solutions
are mirror images of each other. Chaotic cylinder paths are
observed when increasing the natural frequency over a
critical value.
Kiadó neve:
CFD.HU Kft.
Cím:
Natural frequency effect on the path of an elastically supported circular cylinder
Proceedings of Conference on Modelling Fluid Flow (CMFF'18)
Forrásdokumentum szerzői:
J Vad,
Év:
2018
Kiadó:
CFD.HU Kft.
Megjelenési hely:
Budapest
Az adatrekord státusza:
feldolgozás alatt
Megjegyzés/összefoglaló leírás:
Flow around a freely vibrating circular cylinder in two-
degrees-of-freedom is investigated at low Reynolds numbers
using two-dimensional numerical simulation. Systematic
computations are carried out to investigate the effect of
cylinder’s natural frequency fN on the oscillation amplitudes
and aerodynamic force coefficients. The mass ratio and the
structural damping coefficient values are fixed at m*=
10 and
ζ=
0, respectively.
In addition to the typical distorted figure-eight motion, a
raindrop-shaped path is also found whose range widens with
increasing fN. Within this range the streamwise cylinder
oscillation amplitude reaches higher values compared to
figure-eight motions and the curves shift upwards with
increasing fN. Sudden switches in the vortex structure occur
near the upper boundaries separating the raindrop-shaped and
distorted figure-eight motion domains. The root-mean-square
(rms) values of lift plotted against U*St0 shift upwards in
the raindrop-shaped motion range and downwards in the figure-
eight motion range, while the rms of drag shifts to higher
values in both regimes with increasing fN. The time-mean of
lift coefficient jumps abruptly between two solutions. Using
pre- and post-jump analysis it is shown that these solutions
are mirror images of each other. Chaotic cylinder paths are
observed when increasing the natural frequency over a
critical value.