Near-Wake of an Inclined 6:1 Spheroid at Reynolds Number 4000

Abstract

We describe the flow around a 6:1 prolate spheroid at 45 • inclination angle and Reynolds number 4000 based on the minor axis. Despite that the inflow is uniform and steady, the resulting wake is highly asymmetric and unsteady. Two main vortical structures develop from the shear layers of the spheroid, one being significantly stronger than the other. This asymmetry results in a non-zero sideforce. The forces acting on the spheroid change dramatically from earlier works at Reynolds number 3000. The pressure inside the vortex cores also changed with this moderate increase in Reynolds number. This indicates that the flow is highly transitional.We also document that close to the body, on the side of the weaker vortex, there is a region of negative axial velocity. In this backflow region, the fluid enters from behind the spheroid and travels forward against the inflow and then exits the backflow region through one of the main vortical structures. This backflow has not been described before. We also observe and describe a distinct Kelvin-Helmholtz shear layer instability close to this region.x ax Spheroid major axisx, y, z Cartesian coordinatesThis is a post-print. The Online version is found via. AIAA J. website: https://arc.aiaa.org/doi/full/10.2514/1.J057615 where supplementary animation can also be downloaded.

Turbulent wake behind a concave curved cylinder

“…In Thomson & Morrison (1971), the alternating asymmetric flow pattern remained steady up to , whereas in the inclined spheroid wake, we observed a mean side force up to (Strandenes et al. 2019). However, in the present wake, the helical vortex pair directly meets the periodic oblique shedding, and the latter triggers the former to have a periodic motion.…”

“…The code has recently been used for DNS/LES of the same curved cylinder configuration (Jiang et al 2018b) as well as various other flow configurations (e.g. Gallardo et al 2014a;Tian et al 2017;Strandenes et al 2019). MGLET uses a multi-level 3-D Cartesian mesh, and mesh generation is based on a zonal grid algorithm (Manhart 2004).…”

Experimental Study on the Effects of Shear on Co‐Currently Swirling Steam‐Water Flow Instabilities

“…In another studies, the intermittency of the shear-layer fluctuations was found to be irrelevant to the transverse motion of the shear layer. These fluctuations are caused by the movement of the transition point where these fluctuations are generated within the shear layer [13][14][15][16][17].…”