# Can we force turbulent transition of main flow despite unsufficient Reynolds number?

I was wondering something for awhile without finding what I was looking for :

let's consider a flow, for instance inside a pipe, with a Reynolds number $$Re$$ below a critical Reynolds number $$Re_{cr}$$ corresponding to the value below which the main flow remains laminar. Is it possible to force the main flow to swtich to a turbulent regime without changing its velocity, but with some kind of artefacts like vortex generators, or ramps, and so on ?

I am not talking about the transition of the boundary layer from laminar to turbulent. I know that there are many kinds of means to acheive the transition. Plus, usually, when we talk about the laminar/turbulent transition of a boundary layer, the main flow is already turbulent. I am talking about a laminar main flow in a pipe, and we try to make it turbulent by other means than increasing upstream velocity.

Thank you