Inertial flow past moderately yawed cylinders

The flow past a finite-end yawed cylindrical particle is studied numerically. Three dimensionless parameters govern the problem when the flow is steady and uniform: the aspect ratio $\frac{L}{D}$ where $L$ is the length of the cylinder and $D$ its diameter, the yaw angle $\theta$ which is the angle between the cylinder axis and the inlet velocity, and the Reynolds number based on $D$. Particular attention is paid to the effect of these parameters on the particle wake and hydrodynamic loads. The aspect ratio is prescribed in the range $[2;10]$, the yaw angle in the range $[0;30]$, and the Reynolds number in the range $[0;400]$. Various types of vortex patterns are observed, including steady shedding of two counter-rotating vortices, periodic shedding of counter-rotating vortices and unsteady shedding of hairpin-shaped vortices. Results show that the dynamical regime and time evolution of the loads change drastically with the yaw angle $\theta$. The wake is found to be unsteady in the range $Re\in[360;400]$ at small yaw angles $(\theta\leq30°)$ with $\frac{L}{D}=2$. We propose a drag law valid for low and high Reynolds numbers in the case of a cylinder aligned with the flow.