Ok I studied bernoulli and I can see how fluid would travel faster in narrowed regions but in most examples I see when something is narrowed the flow is reduced. Is this because of resistance? Also when there is resistance speed in the narrowed section is reduced right? I like to know what do they mean by this friction. Simply I'm asking in most occasion when something is narrowed the fluid flows slower due to resistance. It might be faster than non narrowed part but it is slow because of resistance(I mean if there was no resistance it would be faster) Is that right?