浸入边界格子玻尔兹曼模拟中机制解析的界面动量传递
Mechanism-Resolved Interface Momentum Transfer in Immersed-Boundary Lattice Boltzmann Simulations
AI总结：
该研究以经典流动案例为探针，解析IB-LBM模拟中边界方案、核函数等对界面动量传递的影响，揭示机制并替代通用方案排序。
AI中文摘要：
圆柱与颗粒流动的浸入边界格子玻尔兹曼（IB-LBM）模拟通常通过边界施加方案、核函数和碰撞模型的排序进行比较，但这类比较会掩盖控制每种响应的机制。本文采用经典的固定圆柱、振荡圆柱和沉降颗粒案例作为欧拉-拉格朗日界面动量传递的受控探针。对于指定物体，直接力（DF）、多直接力（MDF）和分布函数修正（DFC）之间的差异可通过局部无滑移保真度而非通用阻力排序最清晰地区分。对于DFC，hat核与Peskin四点核之间依赖核的阻力系数排序反转，与标记解析修正的空间再分布及由此产生的近边界滑移和压力偏差相关，而非仅与总修正量相关。对于沉降颗粒，单颗粒沉降提供运动物体基准，而双颗粒差分密度尾迹相互作用沉降显示，受尾迹暴露的轻颗粒对力评估中显式内部质量修正更敏感，这是一种依赖构型的有限窗口运动边界闭合响应。在测试工况（雷诺数Re≤200下的指定物体比较、二维及报道的运动颗粒案例）中，针对性的双松弛时间（TRT）和中心矩多松弛时间（CM-MRT）碰撞控制的作用次于边界和闭合机制。所得结果将通用方案排序替换为IB-LBM界面动量传递的机制解析解释。
英文摘要：
Immersed-boundary lattice Boltzmann (IB-LBM) simulations of cylinder and particle flows are usually compared by ranking boundary-enforcement schemes, kernels, and collision models. Such comparisons can obscure the mechanism that controls each response. Here, canonical fixed-cylinder, oscillating-cylinder, and sedimenting-particle cases are used as controlled probes of Eulerian-Lagrangian interface momentum transfer. For prescribed bodies, differences among direct forcing (DF), multi-direct forcing (MDF), and distribution-function correction (DFC) are most clearly discriminated by local no-slip fidelity rather than by a universal drag ranking. For DFC, the kernel-dependent drag-coefficient ranking reversal between the hat and Peskin 4-point kernels is associated with the spatial redistribution of the marker-resolved correction and the resulting near-boundary slip and pressure deviation, rather than the total correction magnitude alone. For sedimenting particles, single-particle settling provides a moving-body baseline, whereas two-particle differential-density wake-interaction sedimentation shows the wake-exposed light particle to be comparatively more sensitive to the explicit internal-mass correction in the force evaluation, a configuration-dependent, finite-window moving-boundary closure response. Targeted two-relaxation-time (TRT) and central-moment multiple-relaxation-time (CM-MRT) collision controls remain secondary to the boundary and closure mechanisms within the tested regimes (prescribed-body comparisons at Re <= 200, two-dimensional, and the reported moving-particle cases). The resulting picture replaces a universal scheme ranking with a mechanism-resolved interpretation of IB-LBM interface momentum transfer.
