The flow past a fixed finite-length circular cylinder, the axis of which makes a nonzero angle with the incoming stream, is studied through fully resolved simulations, from creeping-flow conditions to strongly inertial regimes. The investigation focuses on the way the body aspect ratio $\chi$ (defined as as the length-to-diameter ratio), the inclination angle $\theta$ with respect to the incoming flow, and the Reynolds number Re (based on the cylinder diameter) affect the flow structure past the body and therefore the hydrodynamic loads acting on it. The configuration $\theta =0^{\circ }$ (where the cylinder is aligned with the flow) is first considered from creeping-flow conditions up to $\text{Re}=400$, with aspect ratios up to 20 (10) for $\text{Re}\le 10$ ($\text{Re}\ge 10$). In the low-to-moderate Reynolds-number regime ($\text{Re}\lesssim 5$), influence or the aspect ratio, inclination (from $0^{\circ }$ to ${30}^{\circ }$), and inertial effects are examined by comparing numerical results for the axial and transverse force components and the spanwise torque with theoretical predictions based on the slender-body approximation, possibly incorporating finite-Reynolds-number corrections. Semiempirical models based on these predictions and incorporating finite-length and inertial corrections extracted from the numerical data are derived. For large enough Reynolds numbers ($\text{Re}\gtrsim {10}^2$), separation takes place along the upstream part of the lateral surface of the cylinder, deeply influencing the surface stress distribution. Numerical results are used to build empirical models for the force components and the torque, valid for moderately inclined cylinders ($\left|\theta \right|\lesssim {30}^{\circ }$) of arbitrary aspect ratio up to $\text{Re}\approx 300$ and matching those obtained at low-to-moderate Reynolds number.

中文翻译：

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倾斜的圆柱状棒状颗粒和纤维的流动结构和载荷

通过从蠕变流条件到强惯性状态的完全解析模拟，研究了经过固定的有限长度圆柱体的流动，该圆柱体的轴线与输入流成非零角度。调查侧重于身体纵横比的方式$\chi$ （定义为长径比），倾斜角度 $\theta$相对于流入流量，雷诺数Re（基于圆柱直径）会影响流经主体的流动结构，从而影响作用在主体上的流体动力载荷。配置$\theta =0^{\circ }$ （在圆柱体与流对齐的位置）（首先从蠕动流条件一直到 $\text{关于}=400$，其宽高比最大为20（10） $\text{关于}\le 10$ （$\text{关于}\ge 10$）。在中低雷诺数制（$\text{关于}\lesssim 5$），影响或宽高比，倾斜度（来自 $0^{\circ }$ 至 ${30}^{\circ }$），并通过比较轴向和横向力分量的数值结果以及翼展方向扭矩与惯性效应，并根据细长体近似（可能包含有限雷诺数校正）的理论预测，对惯性效应进行了检查。得出基于这些预测并结合了从数值数据中提取的有限长度和惯性校正的半经验模型。对于足够大的雷诺数（$\text{关于}\gtrsim {10}^{\mathrm{2个}}$），分离沿圆柱体侧面的上游发生，深刻地影响了表面应力的分布。数值结果用于建立力分量和扭矩的经验模型，适用于中等倾斜的圆柱体（$\left|\theta \right|\lesssim {30}^{\circ }$）的任意宽高比 $\text{关于}\approx 300$ 并匹配从低到中等雷诺数获得的那些。