The F-packing algorithm is used to eliminate small voids or “foaming” in flows with significant free-surface breakup. The algorithm works by creating small negative divergences in internal fluid cells, in which the fluid fraction is less than 0.99. It is only used in one-fluid flows with free surfaces.

F-packing算法是用来消除流动过程中较大自由液面破裂时产生的小空穴或者泡沫，它可以用来计算内部流体网格产生的小的负背离，其流体分数小于0.99。它只用在可以产生自由表面的单相流中。

The F-packing algorithm is activated by choosing one of the three options in Numerics > Volume-of-fluid advection > Advanced options > F-packing that activate the model. The default setting is Close up interior voids. When Reduce surface breakup in extreme cases is selected, then additional smoothing of the free surface takes place to reduce its breakup at distortion. On top of that, isolated droplets (i.e., fluid occupying less than one cell) are discarded when Discard isolated fluid drops is chosen.

F-packing算法可以通过下面被激活，Numerics > Volume-of-fluid advection > Advanced options > F-packing，默认是关闭内部空穴。当在极端实例中选择减少液面破裂时，平滑的自由液面就会产生来减少液面的破裂。当选择丢弃孤立流体液滴选项时，在自由液面前端孤立的液滴（流体没有充满一个网格时）就会被丢弃。

The rate of F-packing is proportional to the F-packing coefficient. The default value is 1.0. When it is equal to 0.0 no packing will take place.

Occasionally, pressure changes due to F-packing may significantly interfere with the main flow. An indication of such situation can be a “run away” pressure and/or velocity at a location in the flow, which is out of range of physically meaningful values. In that case a smaller value of the F-packing coefficient may be necessary.

CFPK 默认为1.0
//----------------------
动能的另一个特色是‘背离’。

动能与价格之间所产生的冲突现象称为背离（divergence）,根据市场趋势的不同，有正性背离（positive divergence）和负性背离（negative divergence）之分。上升趋势所产生的背离称为负性背离，而下降趋势所产生的背离称为正性背离。

大多数较大趋势在结束前，至少会有一次背离发生。

要注意的是：背离本身代表市场情况正在恶化或改善中，但并不表示价格趋势已经发生了反转。

我们应该从三个角度衡量背离的重要性：
（1） 背离发生的次数：背离发生的次数越多，所代表的意义就越重要。
（2） 涵盖的时间周期：动能峰位与价格峰位之间所涵盖的时间越长，背离就越重要。
（3） 在价格的最后反转点：如果连续的背离出现，而且最后一个的动能指标勉强维持在零线（均衡线）之上，一般来说，价格会在之后暴跌。