1. Essential boundary condition

Specification of primary variables or dependent variables in the problem at the boundary are called as essential boundary condition.

Eg. u(0)= 0 and u(L)≠0

2. Natural boundary condition

Specification of secondary variables in the problem at the boundary are called as essential boundary condition

Eg. uI(0)= 0 and uI(L)≠0

3. Mixed boundary condition

When boundary condition contains specification of both primary variables and secondary variables, then it is known as mixed boundary condition.

Eg. u(0)= 0 and uI(L)≠0

4. Homogenous boundary condition

When all the boundary values are assigned to zero then they are called as homogenous boundary condition.

Eg. u(0)=0 and u(L)=0

5. Non-homogenous boundary condition

If any one of the boundary condition is non-zero value then it is called as Non-homogenous boundary condition.

Eg. u(0)= 0 and uI(L)≠0