Implementation of Optimality condition

Dear Sir/Madam

I have problem with implementation of an equation in the code. I have a relation as follow:
βˆ‡π’₯=βˆ’(𝑑𝑒/𝑑𝑛)+𝛼𝐹 on inlet

where u is obtained in the former step and is known and F is known also. to reach the descent direction I need to calculate βˆ‡π’₯ on inlet. I don’t know how to implement it in the code. I will be grateful if help me.

Best regards

In the documentation, Β§3.13, it reads

macro dn(u) (N.xdx(u)+N.ydy(u) )

which shows you how to calculate the gradient of u and the vector normal to a boundary (in 2 dimensions).


Dear Denis

Thanks very much. I already wrote the equation but my problem is that how I can say that it is for inlet boundary not the other domain. is any definition for that in the code?

Best regards