Heat induced transition of a stable vortex street

A combined numerical and experimental investigation is presented showing the effect of heat on the stability of a horizontal vortex street for Re_D=75 and Ri_D between 1 and 2. Detailed 2D-HiRes PV experiments are compared with 2D numerical results. The results show that an early transition to 3D of the vortex street takes place for Ri_D>1. Furthermore, the location at which the 2D wake becomes essentially 3D turns out to be dependent on Ri_D. For an increasing addition of heat (increasing Ri_D), this location is shifted into the direction of the cylinder. By applying 3D measuring techniques, such as 3D-PTV and 3D visualisation techniques, the transition process and the behaviour downstream of the transition point are investigated.