which is better, unstructured or structure mesh? which one can get the result faster and better?

i try to simulate mixing of multiphase flow in the reactor.

thanks in advanced.

structured mesh. However depends on the complexity of the model one can opt for unstructured domain or zones.

i have try for my case using structured and unstructured mesh. Structured mesh take much longer time to reach the solution rather than unstructured mesh.

How do you define "reach the solution"? In general, as zubair said prefer stuctered meshes over unstructered ones. Very important not just to compare time but also results...

Regards

always use structured mesh except when geometry is too complex and you have to use unstructured/hybrid grid with second order discretisation.

thanks for all.