Boundary layer thickness

Physically Based Rendering

const float w_cas_cpu[27] = { 8.0f / 27, 2.0f / 27, 2.0f / 27, 2.0f / 27, 2.0f / 27, 2.0f / 27,
2.0f / 27, 1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54,
1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54, 1.0f / 54,
1.0f / 216, 1.0f / 216, 1.0f / 216, 1.0f / 216, 1.0f / 216, 1.0f / 216, 1.0f / 216, 1.0f / 216 };

Inlet - Zouhe

normal boundary - bounce-back

outlet - Impedance characteristic-based boundary condition.

看看impedance-boundary condition.

计算channel flow boundary layer thickness

如何增加sample

根据channel flow boundary layer thickness 条件

分析两种情况管道变细，

1.分辨率较少如果sample点变少，会导致drag force增加，流速不一定增快。

2.分辨率足够，sample点变少，导致流速增快。

http://www.pbr-book.org/3ed-2018/contents.html