有关松弛系数的问题，希望大家参与讨论

sfsm

False-time step relaxation：applied to all solved variables,except P1,R1,R2,RS(?)in the form of positive number
Linear relaxation :all stored variables can use it ,including P1,R1,R2,RS,KE,EP,in the form of negative number
The value of false-time step relaxation：Usually it base on some characteristic time-scale(?),normally the smallest one will be used ,multiplied by some factor(?).
A typical starting point:the domain length divided by the inlet velocity divided by the the number of cells in that direction
以上是我看phoenics文件总结出来的，但是看完后还是不知道如何去确定松弛系数，不知道大家看完后有什么想法？请赐教哦：）上面代问好的地方，是小女子不明白的地方，即不知道她们的具体含义，也请赐教哦：）

songrundong

RS....standard name used to denote the second-phase shadow volume fraction, i.e. that which would be present in the absence of inter-phase mass-transfer. RS is especially useful for the simulation of particle combustion
) FALSDT; ie False-time-step relaxation
Its effect is to add to the phi-balance for each cell a source equal to:
(latest_phi - next_phi) * (mass in cell) / DTFALS(phi)
where latest_phi is the current value of the variable being solved for, and next_phi is that which it will take after adjustment.
This has the effect of making next_phi very close to latest_phi when DTFALS is large, so that changes can occur only after many repetitions of the adjustment process.
A value of DTFALS=1.E-20 would prevent change entirely on many machines, a fact which it is sometimes convenient to exploit, for example when seeking to understand the causes of divergence.
PATCH-wise false-time step under-relaxation can be introduced by means of PATCH and COVAL by using the name SAME in the fourth argument of COVAL. See SAME for further information
这是polis中的文档

sfsm

This has the effect of making next_phi very close to latest_phi when DTFALS is large, so that changes can occur only after many repetitions of the adjustment process. 这段话是说当DTFALS较大时，变化很难产生
A value of DTFALS=1.E-20 would prevent change entirely on many machines, a fact which it is sometimes convenient to exploit, for example when seeking to understand the causes of divergence.这段话诗句个例子，当DTFALS=1.E-20 （应该是很小的数吧）时，would prevent change entirely on many machines。
这两段话是不是矛盾啊，还是我理解的不对啊？