Laminar or turbulent flow?
I am trying to simulate different pipe flows with some obstacles inside:
- stationary ones - these cases are often unable to achieve steady state and transient run is needed, but behaviour of a system is not perfectly repetitve over time;
- rotors, which are moved due to forces exerted by fluid flow with use of six do solver - these are of course inherently unsteady
I am dealing with low Re numbers, like 1400, 1900 etc. which are calculated with respect to diameter of a pipe as a characteristic length and this would indicate laminar flow. Medium inside a pipe is water. However, due to unsteadiness of both cases and presence of such obstacles in flow I am not quite sure if I should use a laminar model or tubulent one (maybe even with some transition model turned on?) Or maybe I should calculate Reynolds number with respect to different characteristic length? I would be really grateful for any tips.
Thank you in advance for your help.