Question

why the bernoulis theorem iz not aplicable for laminar flow.?

Answer 1

Although the derivation assumes steady flow, I suspect Bernoulli’s equation would actually work alright for flow with small scale turbulence. I think the effects of the turbulence would average out. It would not work for flows with large scale turbulence (large eddies on the scales of the object). So it would not work in the wake of a cylinder or sphere, for example.